A131875 Triangle, A000012 * A131844 as infinite lower triangular matrices.

1, 5, 4, 12, 5, 7, 22, 6, 8, 10, 35, 7, 9, 11, 13, 51, 8, 10, 12, 14, 16, 70, 9, 11, 13, 15, 17, 19, 92, 10, 12, 14, 16, 18, 20, 22, 117, 11, 13, 15, 17, 19, 21, 23, 25, 145, 12, 14, 16, 18, 20, 22, 24, 26, 28

Offset

0,2

Comments

Left column = pentagonal numbers, A000326: (1, 5, 12, 22, ...).

Row sums = A001106: (1, 9, 24, 46, 75, 111, ...).

Links

Table of n, a(n) for n=0..54.

Example

First few rows of the triangle:
   1;
   5,  4;
  12,  5,  7;
  22,  6,  8, 10;
  35,  7,  9, 11, 13;
  51,  8, 10, 12, 14, 16;
  70,  9, 11, 13, 15, 17, 19;
  92, 10, 12, 14, 16, 18, 20, 22;
  ...

Crossrefs

Cf. A131844, A001106, A000326.

Sequence in context: A262902 A215332 A298779 * A095871 A284551 A316671

Adjacent sequences: A131872 A131873 A131874 * A131876 A131877 A131878

Keyword

nonn,tabl

Author

Gary W. Adamson, Jul 22 2007

Status

approved