A157497 - OEIS

A157497

Triangle read by rows, A156348 * A127648

1, 1, 2, 1, 0, 3, 1, 4, 0, 4, 1, 0, 0, 0, 5, 1, 6, 9, 0, 0, 6, 1, 0, 0, 0, 0, 0, 7, 1, 8, 0, 16, 0, 0, 0, 8, 1, 0, 18, 0, 0, 0, 0, 0, 9, 1, 10, 0, 0, 25, 0, 0, 0, 0, 10, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 1, 12, 30, 40, 0, 36, 0, 0, 0, 0, 0, 12

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OFFSET

1,3

COMMENTS

Row sums = A157020: (1, 3, 4, 9, 6, 22, 8,...)

LINKS

Table of n, a(n) for n=1..78.

FORMULA

Triangle read by rows, A156348 * A127648. A127648 = an infinite lower triangular matrix with (1, 2, 3,...) as the main diagonal and the rest zeros.

EXAMPLE

First few rows of the triangle =

1, 2;

1, 0, 3;

1, 4, 0, 4;

1, 0, 0, 0, 5;

1, 6, 9, 0, 0, 6;

1, 0, 0, 0, 0, 0, 7;

1, 8, 0, 16, 0, 0, 0, 8;

1, 0, 18, 0, 0, 0, 0, 0, 9;

1, 10, 0, 0, 25, 0, 0, 0, 0, 10;

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11;

1, 12, 30, 40, 0, 36, 0, 0, 0, 0, 0, 12;

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13;

1, 14, 0, 0, 0, 0, 49, 0, 0, 0, 0, 0, 0, 14;

...

Row 4 = (1, 4, 0, 4) = termwise products of (1, 2, 0, 1) and (1, 2, 3, 4)

where (1, 2, 0, 1) = row 4 of triangle A156348.

CROSSREFS

Cf. A156348, A126648, A156020

Sequence in context: A246180 A102057 A276276 * A257961 A225310 A131358

Adjacent sequences: A157494 A157495 A157496 * A157498 A157499 A157500

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson & Mats Granvik, Mar 01 2009

STATUS

approved