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A128116 A128064 * A122432 (unsigned). 0
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 (list; table; graph; refs; listen; history; text; internal format)
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

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Last modified August 10 03:38 EDT 2022. Contains 356029 sequences. (Running on oeis4.)