A006676 Number of paths through an array. (Formerly M4292)

6, 104, 1345, 16344, 200452, 2552192, 34138908, 482076000, 7196676696, 113548220928, 1891322394624, 33205209053184, 613390541616000, 11900521690398720, 242050276080034560, 5152173699467335680, 114574144611434273280

Offset

3,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=3..19.

A. M. Khidr and B. S. El-Desouky, A symmetric sum involving the Stirling numbers of the first kind, European J. Combin., 5 (1984), 51-54.

Formula

a(n) = - Sum_{k=3..n} binomial(k, 3) * s(n+1, n+1-k) * n^(n-k) where s(n, k) are Stirling numbers of the first kind. - Sean A. Irvine, Jun 16 2017

Crossrefs

Sequence in context: A001526 A295940 A106304 * A006768 A055969 A285027

Adjacent sequences: A006673 A006674 A006675 * A006677 A006678 A006679

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Sean A. Irvine, Jun 16 2017

Status

approved