cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A158040 Determinant of power series of gamma matrix with determinant 2!.

Original entry on oeis.org

2, 32, 258, 1664, 9710, 53664, 286762, 1497600, 7691238, 38995360, 195696226, 973894272, 4812812446, 23642953376, 115552680090, 562240972800, 2724987988054, 13161369525408, 63371643947474, 304287501281920, 1457424739149582, 6964697175476128
Offset: 1

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Comments

a(n) = Determinant(A + A^2 + A^3 + A^4 + A^5 + ... + A^n) where A is the submatrix A(1..3,1..3) of the matrix with factorial determinant A = [[1,1,1,1,1,1,...],[1,2,1,2,1,2,...], [1,2,3,1,2,3,...], [1,2,3,4,1,2,...], [1,2,3,4,5,1,...], [1,2,3,4,5,6,...], ...]; note: Determinant A(1..n,1..n) = (n-1)!.

Examples

			a(1) = Determinant(A) = 2! = 2.
		

References

  • G. Balzarotti and P. P. Lava, Le sequenze di numeri interi, Hoepli, 2008.

Crossrefs

Cf. A111490.

Programs

  • Maple
    seq(Determinant(sum(A2^i,i=1..n)),n=1..30);
  • PARI
    vector(100, n, matdet(sum(k=1, n, [1,1,1 ; 1,2,1 ; 1,2,3]^k))) \\ Colin Barker, Jul 13 2014

Formula

Empirical g.f.: 2*x*(8*x^6 -50*x^4 +64*x^3 -25*x^2 +1) / ((x -1)^2*(2*x -1)^2*(2*x^2 -5*x +1)^2). - Colin Barker, Jul 13 2014

Extensions

More terms, and offset changed to 1 by Colin Barker, Jul 13 2014