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A131432 (A000012 * A131431) + (A131431 * A000012) - A000012. 2
1, 4, 7, 7, 10, 13, 10, 13, 16, 19, 13, 16, 19, 22, 25, 16, 19, 22, 25, 28, 31, 19, 22, 25, 28, 31, 34, 37, 23, 26, 29, 32, 35, 38, 41, 45, 26, 29, 32, 35, 38, 41, 44, 48, 51, 29, 32, 35, 38, 41, 44, 47, 51, 54, 57 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Left border = A016777, (1, 4, 7, 10, 13,...). Right border = A016921: (1, 7, 13, 19, 25,...). Row sums = A051682, 11-gonal numbers: (1, 11, 30, 58, 95,...).

LINKS

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

FORMULA

(A000012 * A131431) + (A131431 * A000012) - A000012 as infinite lower triangular matrices.

EXAMPLE

First few rows of the triangle are:

1;

4, 7;

7, 10, 13;

10, 13, 16, 19;

13, 16, 19, 22, 25;

16, 19, 22, 25, 28, 31;

19, 22, 25, 28, 31, 34, 37;

...

CROSSREFS

Cf. A131431, A016777, A016921, A051682.

Sequence in context: A159919 A310929 A310930 * A088744 A168074 A061891

Adjacent sequences:  A131429 A131430 A131431 * A131433 A131434 A131435

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jul 10 2007

STATUS

approved

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Last modified April 22 14:39 EDT 2021. Contains 343177 sequences. (Running on oeis4.)