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Search: id:A025238
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A025238 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-2)*a(2) for n >= 3. +0
5
3, 1, 3, 10, 36, 137, 543, 2219, 9285, 39587, 171369, 751236, 3328218, 14878455, 67030785, 304036170, 1387247580, 6363044315, 29323149825, 135700543190, 630375241380, 2938391049395, 13739779184085, 64430797069375, 302934667061301 (list; graph; listen)
OFFSET

1,1
FORMULA

G.f.: (1+3*x-sqrt(1-6*x+5*x^2))/2 - Michael Somos, Jun 08, 2000.

PROGRAM

(PARI) a(n)=polcoeff((1+3*x-sqrt(1-6*x+5*x^2+x*O(x^n)))/2, n)

CROSSREFS

Essentially same as A002212.

Sequence in context: A058842 A128162 A067329 this_sequence A126970 A001351 A112811

Adjacent sequences: A025235 A025236 A025237 this_sequence A025239 A025240 A025241

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu)

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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