A131248 - OEIS

A131248

2*A004070 - A000012.

1, 1, 1, 1, 3, 1, 1, 3, 5, 1, 1, 3, 7, 7, 1, 1, 3, 7, 13, 9, 1, 1, 3, 7, 15, 21, 11, 1, 1, 3, 7, 15, 29, 31, 13, 1, 1, 3, 7, 15, 31, 51, 43, 15, 1, 1, 3, 7, 15, 31, 61, 83, 57, 17, 1

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OFFSET

0,5

COMMENTS

Row sums = A104161: (1, 2, 5, 10, 19, 34, 59, ...).

LINKS

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

FORMULA

2*A004070 - A000012 as infinite lower triangular matrices. Reversal triangle of A131247, read by rows.

EXAMPLE

First few rows of the triangle:

1, 1;

1, 3, 1;

1, 3, 5, 1;

1, 3, 7, 7, 1;

1, 3, 7, 13, 9, 1;

1, 3, 7, 15, 21, 11, 1;

1, 3, 7, 15, 29, 31, 13, 1;

...

CROSSREFS

Cf. A004070, A000012, A104161, A131247.

Sequence in context: A246685 A218618 A271451 * A116445 A110291 A152027

Adjacent sequences: A131245 A131246 A131247 * A131249 A131250 A131251

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jun 23 2007

STATUS

approved