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.

A303666 Expansion of 1/((1 - x)*(1 - Sum_{k>=0} x^(2^k))).

Original entry on oeis.org

1, 2, 4, 7, 13, 23, 41, 72, 128, 226, 400, 706, 1248, 2204, 3894, 6877, 12149, 21459, 37907, 66957, 118275, 208919, 369037, 651863, 1151453, 2033921, 3592719, 6346167, 11209863, 19801075, 34976589, 61782572, 109132628, 192771658, 340511506, 601478868, 1062451154, 1876711698, 3315020026
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 28 2018

Keywords

Comments

Partial sums of A023359.

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; 1+
         `if`(n>0, add(a(n-2^i), i=0..ilog2(n)), 0)
        end:
    seq(a(n), n=0..50);  # Alois P. Heinz, Apr 28 2018
  • Mathematica
    nmax = 38; CoefficientList[Series[1/((1 - x) (1 - Sum[x^2^k, {k, 0, nmax}])), {x, 0, nmax}], x]
    a[0] = 1; a[n_] := a[n] = Sum[Boole[k == 2^IntegerExponent[k, 2]] a[n - k], {k, 1, n}]; Accumulate[Table[a[n], {n, 0, 38}]]