A129277 Column 1 of triangle A129276; a(n) is the coefficient of q^n in the squared q-factorial of n+1.
1, 2, 8, 42, 241, 1444, 8867, 55320, 349009, 2220242, 14215521, 91487834, 591285123, 3834960060, 24947236547, 162704291214, 1063516446543, 6965286759424, 45696734431169, 300262228345720, 1975679169075314
Offset: 0
Keywords
Links
- Eric Weisstein's World of Mathematics, q-Factorial.
Programs
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PARI
a(n)=polcoeff(prod(i=1,n+1,(1-x^i)/(1-x))^2,n)
Formula
a(n) = [q^n] Product_{i=1..n+1} { (1-q^i)/(1-q) }^2.