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.

A089950 Partial sums of A001652.

Original entry on oeis.org

0, 3, 23, 142, 838, 4897, 28557, 166460, 970220, 5654879, 32959075, 192099594, 1119638514, 6525731517, 38034750617, 221682772216, 1292061882712, 7530688524091, 43892069261871, 255821727047174, 1491038293021214, 8690408031080153, 50651409893459749
Offset: 0

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Author

Charlie Marion, Jan 11 2004

Keywords

Programs

  • PARI
    concat(0, Vec(-x*(-3+x)/((1-6*x+x^2)*(x-1)^2) + O(x^40))) \\ Michel Marcus, Feb 05 2016

Formula

a(n) = Sum_{k=0...n} A001652(k).
a(n) = A000129(n+1)^2-floor((n+2)/2); e.g. 0=1^2-1 and 166460=408^2-4.
G.f.: -x*(-3+x) / ( (1-6*x+x^2)*(x-1)^2 ). - R. J. Mathar, Feb 05 2016
a(n) = (-6 + (3-2*sqrt(2))^(1+n) + 3*(3+2*sqrt(2))^n + 2*sqrt(2)*(3+2*sqrt(2))^n - 4*n) / 8. - Colin Barker, Aug 10 2018