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.

A159347 Transform of the finite sequence (1, 0, -1) by the T_{0,0} transformation.

Original entry on oeis.org

1, 1, 1, 4, 10, 23, 53, 123, 286, 665, 1546, 3594, 8355, 19423, 45153, 104968, 244021, 567280, 1318766, 3065759, 7127025, 16568323, 38516678, 89540413, 208156206, 483904470, 1124941411, 2615171499, 6079536145, 14133206848, 32855719753
Offset: 0

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Author

Richard Choulet, Apr 11 2009

Keywords

Comments

Without the first two 1's: A137531.

Crossrefs

Cf. A137531.

Programs

  • Magma
    I:=[1,4,10]; [1,1] cat [n le 3 select I[n] else 3*Self(n-1) - 2*Self(n-2) + Self(n-3): n in [1..50]]; // G. C. Greubel, Jun 16 2018
  • Maple
    a(0):=1: a(1):=1:a(2):=1: a(3):=4:a(4):=10:for n from 2 to 31 do a(n+3):=3*a(n+2)-2*a(n+1)+a(n):od:seq(a(i),i=0..31);
  • Mathematica
    Join[{1,1}, LinearRecurrence[{3,-2,1}, {1,4,10}, 50]] (* G. C. Greubel, Jun 16 2018 *)
  • PARI
    m=50; v=concat([1,4,10], vector(m-3)); for(n=4, m, v[n] = 3*v[n-1] -2*v[n-2] +v[n-3] ); concat([1,1], v) \\ G. C. Greubel, Jun 16 2018
    

Formula

O.g.f.: f(z) = ((1-z)^2/(1 - 3*z + 2*z^2 - z^3))*(1-z^2).
a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) for n >= 5, with a(0)=1, a(1)=1, a(2)=1, a(3)=4, a(4)=10.
a(n) = A137531(n-2).