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.

A034772 Dirichlet convolution of d(n) (number of divisors) with Fibonacci numbers.

Original entry on oeis.org

1, 3, 4, 8, 7, 18, 15, 34, 41, 71, 91, 182, 235, 409, 628, 1047, 1599, 2685, 4183, 6906, 10980, 17895, 28659, 46756, 75038, 121865, 196496, 318620, 514231, 833426, 1346271, 2180369, 3524764, 5706087, 9227505, 14935978, 24157819, 39096537
Offset: 1

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Programs

  • Mathematica
    Table[Sum[Fibonacci[n/d]*DivisorSigma[0, d], {d, Divisors[n]}], {n, 1, 40}] (* Vaclav Kotesovec, Sep 10 2019 *)

Formula

G.f.: Sum_{k>=1} d(k) * x^k/(1 - x^k - x^(2*k)). - Ilya Gutkovskiy, Jul 23 2019
a(n) ~ ((1+sqrt(5))/2)^n / sqrt(5). - Vaclav Kotesovec, Sep 11 2019