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A128116 A128064 * A122432. 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 are:

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 January 29 01:54 EST 2020. Contains 331328 sequences. (Running on oeis4.)