A110154 G.f.: A(x) = Product_{n>=1} 1/(1 - 4^n*x^n)^(4/4^n); self-convolution of A110156.

1, 4, 20, 84, 380, 1540, 6796, 27380, 117020, 476260, 2002220, 8063316, 33957180, 136489156, 566211660, 2290272692, 9463603036, 38042178340, 157211980652, 631321594900, 2594532576636, 10457495255940, 42791736547980

Offset: 0

Author

Paul D. Hanna, Jul 14 2005

Keywords

• nonn

Examples

			A(x) = 1 + 4*x + 20*x^2 + 84*x^3 + 380*x^4 + 1540*x^5 +... =
1/[(1-4*x)*(1-16*x^2)^(1/4)*(1-64*x^3)^(1/16)*(1-256*x^4)^(1/64)*...]
		

Crossrefs

Cf. A110152, A110153, A110155, A110156.

Programs

PARI

a(n)=polcoeff(prod(k=1,n,1/(1-4^k*x^k+x*O(x^n))^(4/4^k)),n)