A145075 Coefficient of x^(5^n) in Q(x)^(n+1), where Q(x) = Sum_{k>=0} (x^(5^k) + x^(2*5^k) + x^(3*5^k) + x^(4*5^k)).
1, 4, 18, 172, 1881, 25644, 411488, 7581792, 157296141, 3630709734, 92225760033, 2556393882912, 76774488792326, 2483261807354874
Offset: 0
Programs
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PARI
{a(n,q=5)=local(Q=sum(j=0,n,(x^(q^j)-x^(q*q^j))/(1-x^(q^j)+O(x^(q^n+1)))));polcoeff(Q^(n+1),q^n)}
Extensions
a(7)-a(13) from Max Alekseyev, Dec 19 2011