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.

A352499 Irregular triangle read by rows: T(n,k) is the sum of all parts of the partition of n into consecutive parts that contains 2*k-1 parts, and the first element of the column k is in row A000384(k).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 6, 7, 0, 8, 0, 9, 9, 10, 0, 11, 0, 12, 12, 13, 0, 14, 0, 15, 15, 15, 16, 0, 0, 17, 0, 0, 18, 18, 0, 19, 0, 0, 20, 0, 20, 21, 21, 0, 22, 0, 0, 23, 0, 0, 24, 24, 0, 25, 0, 25, 26, 0, 0, 27, 27, 0, 28, 0, 0, 28, 29, 0, 0, 0, 30, 30, 30, 0, 31, 0, 0, 0, 32, 0, 0, 0
Offset: 1

Views

Author

Omar E. Pol, Mar 19 2022

Keywords

Comments

This triangle is formed from the odd-indexed columns of the triangle A285891.

Examples

			Triangle begins:
   1;
   2;
   3;
   4;
   5;
   6,  6;
   7,  0;
   8,  0;
   9,  9;
  10,  0;
  11,  0;
  12, 12;
  13,  0;
  14,  0;
  15, 15, 15;
  16,  0,  0;
  17,  0,  0;
  18, 18,  0;
  19,  0,  0;
  20,  0, 20;
  21, 21,  0;
  22,  0,  0;
  23,  0,  0;
  24, 24,  0;
  25,  0, 25;
  26,  0,  0;
  27, 27,  0;
  28,  0,  0, 28;
  ...
For n = 21 the partitions of 21 into on odd number of consecutive parts are [21] and [8, 7, 6], so T(21,1) = 1 and T(21,2) = 8 + 7 + 6 = 21. There is no partition of 21 into five consecutive parts so T(21,3) = 0.
		

Crossrefs

Row sums give A352257.
Row n has A351846(n) terms.
The number of nonzero terms in row n equals A082647(n).

Programs

  • Mathematica
    A352499[rowmax_]:=Table[Boole[Divisible[n,2k-1]]n,{n,rowmax},{k,Floor[(Sqrt[8n+1]+1)/4]}];A352499[50] (* Paolo Xausa, Apr 12 2023 *)

Formula

T(n,k) = n*A351824(n,k).
T(n,k) = n*[(2*k-1)|n], where 1 <= k <= floor((sqrt(8*n+1)+1)/4) and [] is the Iverson bracket. - Paolo Xausa, Apr 12 2023