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.

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A027151 a(n) = T(n,0) + T(n,1) + ... + T(n,n), T given by A027144.

Original entry on oeis.org

1, 3, 7, 21, 45, 135, 291, 873, 1881, 5643, 12159, 36477, 78597, 235791, 508059, 1524177, 3284145, 9852435, 21229047, 63687141, 137226717, 411680151, 887047443, 2661142329, 5733964809, 17201894427, 37064931183, 111194793549, 239591481525, 718774444575
Offset: 0

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Crossrefs

Cf. A141041 (bisection), A287811 (bisection).

Programs

  • PARI
    Vec((1 + 3*x)*(1 + x^2) / (1 - 6*x^2 - 3*x^4) + O(x^40)) \\ Colin Barker, Jan 18 2018

Formula

G.f.: (1 + 3*x)*(1 + x^2) / (1 - 6*x^2 - 3*x^4).
a(n) = 6*a(n-2) + 3*a(n-4) for n>3. - Colin Barker, Jan 18 2018
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