A145073 Coefficient of x^(3^n) in Q(x)^(n+1), where Q(x) = Sum_{k>=0} (x^(3^k) + x^(2*3^k)).

1, 2, 7, 44, 325, 3110, 34258, 436304, 6246439, 99637730, 1747851787, 33469239848, 694321125511, 15513919320368, 371408549270425, 9484764686963792, 257355204923817028, 7393783957451330630, 224224270472995407877

Offset: 0

Author

Paul D. Hanna, Oct 09 2008

Keywords

• nonn

Crossrefs

Cf. A007178, A145074, A145075, A145076.

Programs

PARI

{ a(n) = local( Q = sum(j=0,n,x^(3^j)+x^(2*3^j)) + O(x^(3^n+1)) ); polcoeff(Q^(n+1),3^n) }

Extensions

a(10)-a(12) from Alois P. Heinz, Apr 28 2009

a(13)-a(18) from Max Alekseyev, Dec 18 2011