A051525 Third unsigned column of triangle A051338.

0, 0, 1, 21, 335, 5000, 74524, 1139292, 18083484, 299705400, 5198985576, 94461323616, 1797180658272, 35776357096896, 744402741205824, 16169795109262080, 366214212167489280, 8636605663418933760

Offset

0,4

Comments

From Johannes W. Meijer, Oct 20 2009: (Start)

The asymptotic expansion of the higher order exponential integral E(x,m=3,n=6) ~ exp(-x)/x^3*(1 - 21/x + 335/x^2 - 5000/x^3 + 74524/x^4 - 1139292/x^5 + ...) leads to the sequence given above. See A163931 and A163932 for more information.

(End)

References

Mitrinovic, D. S. and Mitrinovic, R. S. see reference given for triangle A051338.

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = A051338(n, 2)*(-1)^n; e.g.f.: (log(1-x))^2/(2*(1-x)^6).

If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = |f(n,2,6)|, for n>=1. - Milan Janjic, Dec 21 2008

Crossrefs

Cf. A001725 (m=0), A051524 (m=1) unsigned columns.

Sequence in context: A016191 A297336 A095905 * A107396 A036224 A113895

Adjacent sequences: A051522 A051523 A051524 * A051526 A051527 A051528

Keyword

easy,nonn

Author

Wolfdieter Lang

Status

approved