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.

A294284 Sum of the smaller parts of the partitions of n into two distinct parts with larger part squarefree.

Original entry on oeis.org

0, 0, 1, 1, 2, 1, 3, 6, 9, 7, 10, 8, 11, 8, 12, 17, 22, 28, 34, 31, 37, 33, 40, 48, 56, 51, 59, 53, 60, 53, 61, 70, 79, 72, 82, 93, 104, 97, 109, 122, 135, 128, 142, 135, 149, 140, 154, 169, 184, 199, 214, 204, 219, 235, 251, 268, 285, 274, 292, 281
Offset: 1

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Author

Wesley Ivan Hurt, Oct 26 2017

Keywords

Comments

Sum of the widths of the distinct rectangles with squarefree length and positive integer width such that L + W = n, W < L. For example, a(13) = 11; the rectangles are 2 X 11, 3 X 10, 6 X 7. The sum of the widths is then 2 + 3 + 6 = 11. - Wesley Ivan Hurt, Nov 12 2017

Crossrefs

Programs

  • Mathematica
    Table[Sum[i*MoebiusMu[n - i]^2, {i, Floor[(n-1)/2]}], {n, 60}]
  • PARI
    a(n) = sum(i=1, (n-1)\2, i*moebius(n-i)^2); \\ Michel Marcus, Nov 05 2017

Formula

a(n) = Sum_{i=1..floor((n-1)/2)} i * mu(n-i)^2, where mu is the Möbius function (A008683).