%I A036411
%S A036411 1,9,1089,8281,978121,7436529,878351769,6677994961,788758910641,
%T A036411 5996832038649,708304623404049,5385148492712041,636056763057925561,
%U A036411 4835857349623374369,571178264921393749929,4342594514813297471521
%N A036411 9-gonal square numbers.
%H A036411 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               NonagonalSquareNumber.html">Link to a section of The World of Mathematics.</
               a>
%F A036411 O.g.f f(z)=1+9*z+...= ((1+8*z+182*z^2+8*z^3+z^4)/((1-z)*(1-898*z^2+z^4))). 
               With the first values, for n >+0 : a(n+5)=a(n+4)+898*a(n+3)-898*a(n+2)-a(n+1)+a(n). 
               On every bisection modulo 2 : a(n+2)=30*a(n+1)-a(n)+200. On every 
               bisection modulo 2 : a(n+1)=449*a(n)+100+60*sqrt(56*a(n)^2+25*a(n)). 
               a(n)=(-25/112)+ ((11/28)+(11/112)*sqrt(14))*(15+4*sqrt(14))^n+ ((11/
               28)-(11/112)*sqrt(14))*(15-4*sqrt(14))^n+ ((7/32)-(1/16)*sqrt(14))*(-15+4*sqrt(14))^n+((7/
               32)+(1/16)*sqrt(14))*(-15-4*sqrt(14))^n [From Richard Choulet (richardchoulet(AT)yahoo.fr), 
               May 08 2009]
%p A036411 a(0):=1:a(1):=9:a(2):=1089:a(3):=8281: a(4):=978121:for n from 0 to 20 
               do a(n+5):=a(n+4)+898*a(n+3)-898*a(n+2)-a(n+1)+a(n):od:seq(a(n),n=0..20); 
               [From Richard Choulet (richardchoulet(AT)yahoo.fr), May 08 2009]
%Y A036411 Cf. A048919, A048911, A001106.
%Y A036411 Sequence in context: A099127 A054344 A048912 this_sequence A075412 A084149 
               A020261
%Y A036411 Adjacent sequences: A036408 A036409 A036410 this_sequence A036412 A036413 
               A036414
%K A036411 easy,nonn
%O A036411 1,2
%A A036411 Jean-Francois Chariot (jeanfrancois.chariot(AT)afoc.alcatel.fr)
%E A036411 More terms from Eric Weisstein (eric(AT)weisstein.com)
%E A036411 More terms from Richard Choulet (richardchoulet(AT)yahoo.fr), May 08 
               2009