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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A251701 a(n) = 3^n + n^2.

Original entry on oeis.org

1, 4, 13, 36, 97, 268, 765, 2236, 6625, 19764, 59149, 177268, 531585, 1594492, 4783165, 14349132, 43046977, 129140452, 387420813, 1162261828, 3486784801, 10460353644, 31381060093, 94143179356, 282429537057, 847288610068, 2541865829005, 7625597485716
Offset: 0

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Author

Vincenzo Librandi, Dec 07 2014

Keywords

Crossrefs

Programs

  • Magma
    [3^n+n^2: n in [0..30]];
    
  • Magma
    I:=[1,4,13,36]; [n le 4 select I[n] else 6*Self(n-1)-12*Self(n-2)+10*Self(n-3)-3*Self(n-4): n in [1..30]];
  • Maple
    A251701:=n->3^n + n^2: seq(A251701(n), n=0..40); # Wesley Ivan Hurt, Jan 22 2017
  • Mathematica
    Table[3^n + n^2, {n, 0, 40}] (* or *) CoefficientList[Series[(1 - 2 x + x^2 - 4 x^3) / ((1 - 3 x) (1 - x)^3), {x, 0, 40}], x]
    LinearRecurrence[{6,-12,10,-3},{1,4,13,36},30] (* Harvey P. Dale, Aug 08 2017 *)

Formula

G.f.: (1-2*x+x^2-4*x^3)/((1-3*x)*(1-x)^3).
a(n) = 6*a(n-1)-12*a(n-2)+10*a(n-3)-3*a(n-4) for n>3.
a(n) = A000244(n) + A000290(n).
Previous Showing 11-11 of 11 results.