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.

A329275 Expansion of 1 / (1 + Sum_{k>=1} mu(k) * log(1 - 2 * x^k) / k), where mu = A008683.

Original entry on oeis.org

1, 2, 5, 14, 40, 116, 336, 976, 2835, 8238, 23940, 69580, 202235, 587822, 1708606, 4966420, 14436034, 41961830, 121972548, 354544354, 1030574824, 2995634338, 8707595956, 25310916258, 73572844430, 213858876100, 621637274730, 1806952922994, 5252386090589, 15267448253302
Offset: 0

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Author

Ilya Gutkovskiy, Nov 11 2019

Keywords

Comments

Invert transform of A001037.

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1, (2^n-add(
          d*b(d), d=numtheory[divisors](n) minus {n}))/n)
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-i)*b(i), i=1..n))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Nov 11 2019
  • Mathematica
    nmax = 29; CoefficientList[Series[1/(1 + Sum[MoebiusMu[k] Log[1 - 2 x^k]/k, {k, 1, nmax}]), {x, 0, nmax}], x]
    a[0] = 1; a[n_] := a[n] = Sum[(1/k) DivisorSum[k, MoebiusMu[#] 2^(k/#) &] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 29}]

Formula

a(0) = 1; a(n) = Sum_{k=1..n} A001037(k) * a(n-k).