A381428 E.g.f. A(x) satisfies A(x) = 1/( 1 - sinh(x) * A(x)^2 ).
1, 1, 6, 73, 1344, 33481, 1054656, 40223233, 1802385024, 92827015921, 5403527705856, 350854589607193, 25142008355656704, 1971003462240791161, 167802783944207917056, 15417877986778302551953, 1520661128893781018640384, 160249491538400609431567201, 17969682580669053325124960256
Offset: 0
Keywords
Programs
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PARI
a136630(n, k) = 1/(2^k*k!)*sum(j=0, k, (-1)^(k-j)*(2*j-k)^n*binomial(k, j)); a(n) = sum(k=0, n, k!*binomial(3*k+1,k)/(3*k+1)*a136630(n, k));
Formula
a(n) = Sum_{k=0..n} k! * binomial(3*k+1,k)/(3*k+1) * A136630(n,k).