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A129278 Column 2 of triangle A129276; a(n) is the coefficient of q^(2n+2) in the squared q-factorial of n+2. 3
1, 8, 106, 1558, 23589, 360499, 5530445, 85040656, 1310211074, 20223812711, 312728963211, 4844238210807, 75161494829564, 1167972975649534, 18175688264003359, 283219807758089612, 4418626917709277371 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

Eric Weisstein's World of Mathematics, q-Factorial from MathWorld.

FORMULA

a(n) = [q^(2n+2)] Product_{i=1..n+2} { (1-q^i)/(1-q) }^2.

PROG

(PARI) a(n)=polcoeff(prod(i=1, n+2, (1-x^i)/(1-x))^2, 2*n+2)

CROSSREFS

Cf. A129276, A129277.

Sequence in context: A024358 A055406 A155632 * A112701 A099695 A236953

Adjacent sequences:  A129275 A129276 A129277 * A129279 A129280 A129281

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Apr 07 2007

STATUS

approved

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Last modified November 15 08:37 EST 2019. Contains 329144 sequences. (Running on oeis4.)