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A108225 a(0) = 0, a(1) = 2; for n >= 2, a(n) = (a(n-1)+a(n-2))*(a(n-1)-a(n-2)+1)/2. +0
2
0, 2, 3, 5, 12, 68, 2280, 2598062, 3374961778893, 5695183504492614029263280, 16217557574922386301420536972254869595782763547562 (list; graph; listen)
OFFSET

0,2

COMMENT

From a posting by Antreas P. Hatzipolakis to the Yahoo news group "Hyacinthos", circa Jun 10 2005

FORMULA

Conjecture: a(n)=A006894(n)+1. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 23 2007

MAPLE

F:=proc(n) option remember; if n <= 1 then RETURN(2*n) fi; (F(n-1)+F(n-2))*(F(n-1)-F(n-2)+1)/2; end;

a[ -2]:=-2:a[ -1]:=0:a[0]:=1:for n from 1 to 50 do a[n]:=binomial(a[n-1]+2, 2) od: seq(a[n]+2, n=-2..8); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 08 2007

CROSSREFS

First differences give A103410.

Adjacent sequences: A108222 A108223 A108224 this_sequence A108226 A108227 A108228

Sequence in context: A008323 A000997 A107475 this_sequence A133832 A061488 A111239

KEYWORD

nonn

AUTHOR

njas, Jun 16 2005

EXTENSIONS

The next term is too large to include.

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Last modified October 8 07:34 EDT 2008. Contains 144666 sequences.


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