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.

A024197 a(n) = 3rd elementary symmetric function of the first n+2 odd positive integers.

Original entry on oeis.org

15, 176, 950, 3480, 10045, 24640, 53676, 106800, 197835, 345840, 576290, 922376, 1426425, 2141440, 3132760, 4479840, 6278151, 8641200, 11702670, 15618680, 20570165, 26765376, 34442500, 43872400, 55361475, 69254640, 85938426, 105844200, 129451505
Offset: 1

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Crossrefs

Contribution from Johannes W. Meijer, Jun 08 2009: (Start)
Equals fourth right hand column of A028338 triangle.
Equals fourth left hand column of A109692 triangle.
Equals fourth right hand column of A161198 triangle divided by 2^m.
(End)

Programs

  • PARI
    Vec(-x*(x^3+33*x^2+71*x+15)/(x-1)^7 + O(x^100)) \\ Colin Barker, Aug 15 2014

Formula

a(n) = n*(n+1)*(n+2)^2*(n^2+3*n+1)/6.
G.f.: -x*(x^3+33*x^2+71*x+15) / (x-1)^7. - Colin Barker, Aug 15 2014
a(n) = A004320(n)*A028387(n). - R. J. Mathar, Oct 01 2016
a(n) = A028338(n+2, n-1), n >= 1, (fourth diagonal). See a crossref. below. - Wolfdieter Lang, Jul 21 2017