A281430 - OEIS

%I #4 May 21 2017 07:48:22

%S 1,4,104,6880,855680,171673600,50628300800,20616410214400,

%T 11081874771968000,7600553402810368000,6477130108444835840000,

%U 6713789344917138964480000,8317650472128427128258560000,12137529532422860667092992000000

%N E.g.f.: C(x)^4 where C(x) is described by A281428.

%e C(x)^4 = 1 + 4*x^2/2! + 104*x^4/4! + 6880*x^6/6! + 855680*x^8/8! + 171673600*x^10/10! + 50628300800*x^12/12! + 20616410214400*x^14/14! + 11081874771968000*x^16/16! + 7600553402810368000*x^18/18! + 6477130108444835840000*x^20/20! + 6713789344917138964480000*x^22/22! + 8317650472128427128258560000*x^24/24! +...

%o (PARI) {a(n) = my(S=x, C=1); for(i=0, n, S = intformal( C^5 +x*O(x^(2*n))); C = 1 + intformal( S*C^4 ) ); (2*n)!*polcoeff(C^4, 2*n)}

%o for(n=0, 30, print1(a(n), ", "))

%Y Cf. A281428.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Feb 01 2017