# format_V.txt

kernelopts(printbytes=false):
with(share): with(gfun):

# Last modified Nov 30 1998

# Maple V procedure that takes a sequence of integers in Maple "list"
#	format and converts it to the format I use in the
#	Integer Sequences Table.

# MEMO to other users:
#	YOU MUST EDIT THIS FILE AND REPLACE EVERY INSTANCE OF 
#		"ampersand amp;" by an "ampersand"
#		"ampersand lt;"  by a  "less than"
#		"ampersand gt;"  by a  "greater than"
#
#       Also replace "njas"
#	by your name and email address
#	Preferred format for this is 
#	Mary Smith (ms@math.univ.edu)
#	using parens () not pointed brackets because the latter
#	cause trouble with html

# The second argument , e.g. 2632, is the sequence ID number.
# Best to use 0,1,2,3 ... since I assign ID numbers as the sequences arrive.

# Send new sequences to me at this address:  njas@research.att.com
# Thanks!  Neil Sloane

# EXAMPLES:  (Call this file "format")

#      There is a finished example a bit further down.
#      Note that that includes a %H line with a link to a web site
#      where more information about the sequence can be found.
#      Please add such links if appropriate!

# $ maple
# > read format;

# > seq1:=[1,2,5,16,73,538];
# > format(seq1,2632);
# %I A002632
# %S A002632 1,2,5,16,73,538
# %N A002632       # please describe sequence in %N line
# %O A002632 0,2   # offset line (see help file for details)
# %K A002632 nonn  # keywords (see help file for details)
# %A A002632 njas  # put your name here - see above
# %D A002632       # Give detailed references in 1 or more %D lines
# %p A002632       # give Maple commands here if appropriate

# > seq2:=[seq(2^n,n=0..50)]:
# > format(seq2,79);
# %I A000079
# %S A000079 1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,
# %T A000079 32768,65536,131072,262144,524288,1048576,2097152,4194304,
# %U A000079 8388608,16777216,33554432,67108864,134217728,268435456
# %N A000079
# %O A000079 0,2
# %K A000079 nonn
# %A A000079 njas
# %D A000079
# %p A000079

# It handles signed sequences too:
# > seq3:=[seq( (-1)^n*2^n,n=0..50) ]:
# > format(seq3,10059);
# %I A010059
# %S A010059 1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,
# %T A010059 32768,65536,131072,262144,524288,1048576,2097152,4194304,
# %U A010059 8388608,16777216,33554432,67108864,134217728,268435456
# %V A010059 1,-2,4,-8,16,-32,64,-128,256,-512,1024,-2048,4096,-8192,16384,
# %W A010059 -32768,65536,-131072,262144,-524288,1048576,-2097152,4194304,
# %X A010059 -8388608,16777216,-33554432,67108864,-134217728,268435456
# %N A010059
# %O A010059 0,2
# %K A010059 sign,done
# %A A010059 njas
# %D A010059
# %p A010059

# > quit

# Here is a typical example of a finished sequence:
# %I A000745
# %S A000745 1,5,18,57,180,617,2400,10717,54544,312353,1988104,13921501,
# %T A000745 106350816,880162337,7844596536,74910367309,763030711936,
# %U A000745 8257927397569,94628877364936,1144609672707741,14573622985067744
# %N A000745 Boustrophedon transform of squares.
# %O A000745 0,2
# %K A000745 nonn
# %A A000745 njas
# %p A000745
# %D A000745 J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon transform, J. Comb. Theory, Series A, Vol. 76 (1996), 44-54.
# %H A000745 <a href="http://silk.research.att.com/~njas/doc/bous.ps">Link to reference</a>


format:=proc(s,n)
global A;
local ___A___,pnum,poo,maxn,i,aa,nn,chaineI,chaineN,chainep,chaineD,chaineS,chaineT,\
offset,flg,chaineA,chaineO,chaineU,pn,pa,pi,po,ps,pt,pu,pv,pw,px,pk,pp,pd,\
blanc,chaineV,chaineW,chaineX,ls,lt,lu,lv,lw,lx,sig,chaineK,t1;
# save old A
___A___:=A;
A:='A';
t1:=1000000000+n;
maxn:=64;
offset:=1;
flg:=0;
pn:=`%N `;
pa:=`%A `;
pi:=`%I `;
po:=`%O `;
ps:=`%S `;
pt:=`%T `;
pu:=`%U `;
pv:=`%V `;
pw:=`%W `;
px:=`%X `;
pk:=`%K `;
pp:=`%p `;
pd:=`%D `;
pnum:=convert(t1,string);
pnum:=substring(pnum,5..10);
pnum:=cat(`A`,pnum);
aa:=s;
nn:=nops(aa);
blanc:=` `;
chaineS:=` `;
chaineT:=` `;
chaineU:=` `;
chaineV:=` `;
chaineW:=` `;
chaineX:=` `;
chaineA:=cat(pa,pnum,blanc,`njas`);
chaineI:=cat(pi,pnum);
chaineN:=cat(pn,pnum);
chaineK:=cat(pk,pnum);
chainep:=cat(pp,pnum);
chaineD:=cat(pd,pnum);
i:=1;
chaineS:=cat(ps,pnum,blanc,abs(op(i,aa)));
chaineV:=cat(pv,pnum,blanc,    op(i,aa) );
if i<nn then chaineS:=cat(chaineS,`,`) fi;
if i<nn then chaineV:=cat(chaineV,`,`) fi;
if abs(op(i,aa)) > 1 and flg=0 then offset:=i:flg:=1 fi;
chaineT:=cat(pt,pnum,blanc);
chaineU:=cat(pu,pnum,blanc);
chaineW:=cat(pw,pnum,blanc);
chaineX:=cat(px,pnum,blanc);
while length(chaineS) <= maxn and i<nn do
      i:=i+1;
      chaineS:=cat(chaineS,abs(op(i,aa)),`,`);
      chaineV:=cat(chaineV,    op(i,aa) ,`,`);
      if abs(op(i,aa)) > 1 and flg=0 then offset:=i:flg:=1 fi;
od;

while  i < nn and length(chaineT) <= maxn do
       i:=i+1;
       chaineT:=cat(chaineT,abs(op(i,aa)),`,`);
       chaineW:=cat(chaineW,    op(i,aa) ,`,`);
od;

while  i < nn and length(chaineU) <= maxn do
       i:=i+1;
       chaineU:=cat(chaineU,abs(op(i,aa)),`,`);
       chaineX:=cat(chaineX,    op(i,aa) ,`,`);
od;

poo:=cat(` 0,`,convert(offset,string));
chaineO:=cat(po,pnum,poo);

ls:=length(chaineS);
lt:=length(chaineT);
lu:=length(chaineU);
lv:=length(chaineV);
lw:=length(chaineW);
lx:=length(chaineX);
if lt = 11 then
	chaineS:=substring(chaineS,1..ls-1);
	chaineV:=substring(chaineV,1..lv-1);
	fi;
if lu = 11 then
	chaineT:=substring(chaineT,1..lt-1);
	chaineW:=substring(chaineW,1..lw-1);
	fi;
chaineU:=substring(chaineU,1..lu-1);
chaineX:=substring(chaineX,1..lx-1);

sig:=1:
for i from 1 to nn do if op(i,aa)<0 then sig:=-1: fi: od:
lprint(chaineI);
lprint(chaineS);
if lt>11 then lprint(chaineT); fi:
if lu>11 then lprint(chaineU); fi:

if sig<0 then
	lprint(chaineV);
	if lt>11 then lprint(chaineW); fi:
	if lu>11 then lprint(chaineX); fi:
	chaineK:=cat(chaineK,blanc,`sign,done`):
else
	chaineK:=cat(chaineK,blanc,`nonn`):
fi:
A:=___A___;
lprint(chaineN);
lprint(chaineO);
lprint(chaineK);
lprint(chaineA);
lprint(chaineD);
lprint(chainep);
end:

# END OF PROGRAM