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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A349542 Number of partitions of n into distinct unitary divisors of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2
Offset: 0

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Author

Ilya Gutkovskiy, Nov 21 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := SeriesCoefficient[Product[(1 + Boole[GCD[n/d, d] == 1] x^d), {d, Divisors[n]}], {x, 0, n}]; Table[a[n], {n, 0, 114}]
  • PARI
    A349542(n) = if(!n, 1, my(p=1); fordiv(n,d, if(1==gcd(d,n/d), p *= (1 + 'x^d))); polcoeff(p,n)); \\ Antti Karttunen, Nov 22 2021

Formula

a(n) = [x^n] Product_{d|n, gcd(d,n/d) = 1} (1 + x^d).
Showing 1-1 of 1 results.