A372796 E.g.f. A(x) satisfies A(A(A(A(x)))) = (-1/8) * log(1 - 8*x).

0, 1, 2, 14, 168, 2776, 56672, 1342864, 35866368, 1089119616, 39079100032, 1656388518144, 73919648645632, 2888230034093056, 104369370522809344, 10598445084195061760, 1502420051590162006016, 39363517546114295169024, -23019065875812133365235712

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Formula

Define the sequence b(n,m) as follows. If n<m, b(n,m) = 0, else if n=m, b(n,m) = 1, otherwise b(n,m) = 1/4 * ( 8^(n-m) * |Stirling1(n,m)| - Sum_{l=m+1..n-1} (b(n,l) + Sum_{k=l..n} (b(n,k) + Sum_{j=k..n} b(n,j) * b(j,k)) * b(k,l)) * b(l,m) ). a(n) = b(n,1).

Crossrefs

Cf. A220112, A372698, A372747.

Cf. A372795.

Sequence in context: A124215 A355781 A003582 * A277373 A084946 A047055

Adjacent sequences: A372793 A372794 A372795 * A372797 A372798 A372799

Keyword

sign

Author

Seiichi Manyama, May 13 2024

Status

approved