A128137 A002260 * A128132.

1, -1, 4, -1, 1, 9, -1, 1, 5, 16, -1, 1, 5, 11, 25, -1, 1, 5, 11, 19, 36, -1, 1, 5, 11, 19, 29, 49, -1, 1, 5, 11, 19, 29, 41, 64, -1, 1, 5, 11, 19, 29, 41, 55, 81, -1, 1, 5, 11, 19, 29, 41, 55, 71, 100

Offset

1,3

Comments

Deleting the right and left borders gives terms of A028387: (1, 5, 11, 29, 29, 41, 55, 71, ...). Row sums = A064999: (1, 3, 9, 21, 41, ...).

Links

Table of n, a(n) for n=1..55.

Formula

A002260 * A128132 as infinite lower triangular matrices.

Example

First few rows of the triangle:
   1;
  -1, 4;
  -1, 1, 9;
  -1, 1, 5, 16;
  -1, 1, 5, 11, 25;
  -1, 1, 5, 11, 19, 36;
  -1, 1, 5, 11, 19, 29, 49;
  ...

Crossrefs

Cf. A002260, A128132, A028387, A128136, A064999.

Sequence in context: A272867 A206438 A331148 * A232530 A346877 A231987

Adjacent sequences: A128134 A128135 A128136 * A128138 A128139 A128140

Keyword

tabl,sign

Author

Gary W. Adamson, Feb 16 2007

Status

approved