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.

A255471 a(n) = A255470(2^n-1).

Original entry on oeis.org

1, 6, 24, 100, 396, 1596, 6364, 25500, 101916, 407836, 1631004, 6524700, 26097436, 104392476, 417564444, 1670268700, 6681052956, 26724255516, 106896934684, 427587913500, 1710351304476, 6841405916956, 27365622269724, 109462491875100, 437849961907996, 1751399858816796, 7005599412897564, 28022397696329500, 112089590695839516
Offset: 0

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Keywords

Crossrefs

Cf. A255470.

Programs

  • PARI
    Vec((1+3*x) / ((1-x)*(1+2*x)*(1-4*x)) + O(x^30)) \\ Colin Barker, Feb 04 2017

Formula

G.f.: (1+3*x)/((1-x)*(1+2*x)*(1-4*x)).
From Colin Barker, Feb 04 2017: (Start)
a(n) = (-4 - (-2)^n + 7*2^(1+2*n)) / 9.
a(n) = 3*a(n-1) + 6*a(n-2) - 8*a(n-3) for n>2.
(End)