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.

A340249 Sum of the largest parts t of the partitions of n into 4 parts q,r,s,t such that 1 <= q <= r <= s <= t and q + r + s > t.

Original entry on oeis.org

0, 0, 0, 1, 2, 2, 5, 8, 14, 18, 30, 35, 56, 63, 95, 109, 156, 166, 235, 255, 346, 369, 491, 517, 676, 707, 907, 952, 1200, 1239, 1548, 1605, 1974, 2037, 2481, 2550, 3078, 3156, 3774, 3874, 4592, 4685, 5522, 5642, 6596, 6726, 7818, 7958, 9200, 9354, 10754, 10939, 12510
Offset: 1

Views

Author

Wesley Ivan Hurt, Jan 01 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Sum[Sum[(n - i - j - k) Sign[Floor[(i + k + j)/(n - i - j - k + 1)]], {i, j, Floor[(n - j - k)/2]}], {j, k, Floor[(n - k)/3]}], {k, Floor[n/4]}], {n, 60}]

Formula

a(n) = Sum_{k=1..floor(n/4)} Sum_{j=k..floor((n-k)/3)} Sum_{i=j..floor((n-j-k)/2)} sign(floor((i+k+j)/(n-i-j-k+1))) * (n-i-j-k).