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.

A133726 Möbius transform of the Pell numbers (A000129).

Original entry on oeis.org

1, 1, 4, 10, 28, 64, 168, 396, 980, 2348, 5740, 13780, 33460, 80612, 194992, 470424, 1136688, 2743160, 6625108, 15992040, 38613792, 93216616, 225058680, 543325464, 1311738092, 3166782500, 7645369060, 18457475260, 44560482148, 107578322912, 259717522848
Offset: 1

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Author

Gary W. Adamson, Sep 21 2007

Keywords

Examples

			a(4) = 10 = (0, -1, 0, 1) dot (1, 2, 5, 12) = (0, -2, 0, 12).
		

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= n-> add(mobius(n/d)*(<<0|1>, <1|2>>^d. <<0,1>>)[1,1], d=divisors(n)):
    seq(a(n), n=1..40);  # Alois P. Heinz, Sep 26 2011
  • Mathematica
    a[n_] := Sum[MoebiusMu[n/d]*(MatrixPower[{{0, 1}, {1, 2}}, d]. {0, 1})[[1]], {d, Divisors[n]}];
    Table[a[n], {n, 1, 40}] (* Jean-François Alcover, Apr 19 2025, after Alois P. Heinz *)

Formula

a(n) = Sum_{d|n} A008683(n/d)*A000129(d) = Sum_{k=1..n} A054525(n,k) * A000129(k).
G.f.: Sum_{k>=1} mu(k) * x^k / (1 - 2*x^k - x^(2*k)). - Ilya Gutkovskiy, Feb 06 2020