A128116 A128064 * A122432 (unsigned).

1, 5, 2, 12, 7, 3, 22, 15, 9, 4, 35, 26, 18, 11, 5, 51, 40, 30, 21, 13, 6, 70, 57, 45, 34, 24, 15, 7, 92, 77, 63, 50, 38, 27, 17, 8, 117, 100, 84, 69, 55, 42, 30, 19, 9, 145, 126, 108, 91, 75, 60, 46, 33, 21, 10

Offset

1,2

Comments

Left border of the triangle = A000326, the pentagonal numbers: (1, 5, 12, 22, 35, ...).

Row sums = A002412: (1, 7, 22, 50, 95, ...).

Links

Table of n, a(n) for n=1..55.

Formula

A128064 * A122432 (unsigned), where the unsigned version of A122432 = (1; 3, 1; 6, 3, 1; 10, 6, 3, 1; ...).

Example

First few rows of the triangle:
   1;
   5,  2;
  12,  7,  3;
  22, 15,  9,  4;
  35, 26, 18, 11,  5;
  51, 40, 30, 21, 13,  6;
  70, 57, 45, 34, 24, 15,  7;
  ...

Crossrefs

Cf. A128064, A122432, A000326, A002412.

Sequence in context: A286142 A286143 A130298 * A082153 A283944 A294684

Adjacent sequences: A128113 A128114 A128115 * A128117 A128118 A128119

Keyword

nonn,tabl

Author

Gary W. Adamson, Feb 14 2007

Status

approved