A381445 E.g.f. A(x) satisfies A(x) = 1/( 1 - x * cosh(x) * A(x)^2 ).
1, 1, 6, 75, 1392, 34925, 1108080, 42562807, 1920796416, 99628495353, 5840628226560, 381927689957891, 27562916396961792, 2176123474607538469, 186580455503952427008, 17264834430223073672175, 1714909152672462179205120, 182002038900785304200753777, 20553746198157175799599202304
Offset: 0
Keywords
Programs
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PARI
a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j)); a(n) = sum(k=0, n, k!*binomial(3*k+1, k)/(3*k+1)*a185951(n, k));
Formula
a(n) = Sum_{k=0..n} k! * binomial(3*k+1,k)/(3*k+1) * A185951(n,k).
Comments