A051546 Third unsigned column of triangle A051339.

0, 0, 1, 24, 431, 7155, 117454, 1961470, 33775244, 603682596, 11235811536, 218055250512, 4413843664416, 93156324734304, 2048591287486080, 46898664421553280, 1116592842912341760, 27618683992928743680

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=7) ~ exp(-x)/x^3*(1 - 24/x + 431/x^2 - 7155/x^3 + 117454/x^4 + ...) 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 A051339.

Links

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

Formula

a(n) = A051339(n, 2)*(-1)^n; e.g.f.: (log(1-x))^2/(2*(1-x)^7).

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,2,7)|, for n>=1. - Milan Janjic, Dec 21 2008

Crossrefs

Cf. A001730 (m=0), A051545 (m=1) unsigned columns.

Sequence in context: A062193 A016268 A175199 * A209448 A264504 A081128

Adjacent sequences: A051543 A051544 A051545 * A051547 A051548 A051549

Keyword

easy,nonn

Author

Wolfdieter Lang

Status

approved