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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.

A261013 Irregular triangle read by rows: T(n,k) = number of partitions of n into prime parts in which the largest part is the k-th prime.

Original entry on oeis.org

0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 2, 1, 1, 1, 1, 2, 1, 0, 2, 2, 1, 1, 1, 2, 2, 2, 0, 0, 2, 3, 2, 1, 1, 1, 2, 3, 3, 1, 0, 0, 3, 4, 3, 1, 1, 1, 2, 4, 4, 2, 1, 0, 3, 5, 5, 2, 1, 1, 1, 3, 5, 5, 3, 2, 0, 0, 3, 6, 7, 3, 2, 1, 1, 1, 3, 7, 7, 4, 3, 1, 0
Offset: 1

Views

Author

N. J. A. Sloane, Aug 16 2015

Keywords

Examples

			Triangle begins:
0,
1,
0,1,
1,0,
0,1,1,
1,1,0,
0,1,1,1,
1,1,1,0,
0,2,1,1,
1,1,2,1,
...
		

Crossrefs

Row sums are A000607.

Programs

  • Maple
    with(numtheory):
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          b(n, i-1)+(p-> `if`(p>n, 0, b(n-p, i)))(ithprime(i))))
        end:
    T:= n-> `if`(n=1, 0, seq(b(n-ithprime(k), k), k=1..pi(n))):
    seq(T(n), n=1..25);  # Alois P. Heinz, Aug 16 2015
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, 1, If[i < 1, 0, b[n, i-1] + Function[p, If[p>n, 0, b[n-p, i]]][Prime[i]]]]; T[n_] := If[n == 1, 0, Table[b[n - Prime[k], k], {k, 1, PrimePi[n]}]]; Table[T[n], {n, 1, 25}] // Flatten (* Jean-François Alcover, Dec 06 2016 after Alois P. Heinz *)

Extensions

More terms from Alois P. Heinz, Aug 16 2015