A381206 - OEIS

%I #10 Feb 17 2025 08:18:12

%S 1,2,6,30,192,1450,12960,133574,1550976,20055186,285903360,4452231982,

%T 75186726912,1368588922298,26709799753728,556339845854550,

%U 12318065768693760,288894650033594914,7154212267816648704,186545064693433665854,5108590743587243950080

%N Expansion of e.g.f. 1/(1 - x*cosh(x))^2.

%C As stated in the comment of A185951, A185951(n,0) = 0^n.

%F a(n) = Sum_{k=0..n} (k+1)! * A185951(n,k).

%o (PARI) a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j));

%o a(n) = sum(k=0, n, (k+1)!*a185951(n, k));

%Y Cf. A205571, A381207.

%Y Cf. A185951.

%K nonn,new

%O 0,2

%A _Seiichi Manyama_, Feb 17 2025