|
Search: id:A164003
|
|
| |
|
| 0, 3, 8, 15, 24, 35, 48, 63, 80, 99, 120, 143, 168, 195, 224, 255, 288, 323, 360, 399, 440, 483, 528, 575, 624, 675, 728, 783, 840, 899, 960, 1023, 1088, 1155, 1224, 1295, 1368, 1443, 1520, 1599, 1680, 1763, 1848, 1935, 2024, 2115, 2208, 2303, 2400, 2499, 2600
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
This sequence should be compared with A005563! (See A163280).
|
|
FORMULA
|
a(n)=2*n+a(n-1)-1 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 07 2009]
|
|
EXAMPLE
|
For n=2, a(2)=2*2+0-1=3; n=3, a(3)=2*3+3-1=8; n=4, a(4)=2*4+8-1=15 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 07 2009]
|
|
MAPLE
|
A033676 := proc(n) local a, d; a := 0 ; for d in numtheory[divisors](n) do if d^2 <= n then a := max(a, d) ; fi; od: a; end: A163280 := proc(n, k) local r, T ; r := 0 ; for T from k^2 by k do if A033676(T) = k then r := r+1 ; if r = n then RETURN(T) ; fi; fi; od: end: A164003 := proc(n) if n = 0 then 0; else A163280(3, n) ; fi; end: seq(A164003(n), n=0..80) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 09 2009]
|
|
CROSSREFS
|
Cf. A002378, A008578, A161344, A161345, A163280, A164000, A164004.
Sequence in context: A005563 A132411 A147998 this_sequence A067998 A060615 A022451
Adjacent sequences: A164000 A164001 A164002 this_sequence A164004 A164005 A164006
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
Omar E. Pol (info(AT)polprimos.com), Aug 08 2009
|
|
EXTENSIONS
|
Extended beyond a(12) by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 09 2009
|
|
|
Search completed in 0.002 seconds
|
