A128078 A002260 * A128064.

1, -1, 4, -1, -2, 9, -1, -2, -3, 16, -1, -2, -3, -4, 25, -1, -2, -3, -4, -5, 36, -1, -2, -3, -4, -5, -6, 49, -1, -2, -3, -4, -5, -6, -7, 64

Offset

1,3

Comments

Row sums = the triangular numbers: (1, 3, 6, 10, ...).

Row sums of A128077 = A000326, the pentagonal numbers: (1, 5, 12, 22, 35, ...).

Links

Table of n, a(n) for n=1..36.

Formula

A002260 * A128064 as infinite lower triangular matrices. Retain the right border of A128077 and change the signs of all other terms to (-).

Example

First few rows of the triangle:
   1;
  -1,  4;
  -1, -2,  9;
  -1, -2, -3, 16;
  ...

Crossrefs

Cf. A002260, A128064, A128077, A000326.

Sequence in context: A279816 A004160 A128077 * A331152 A264922 A341030

Adjacent sequences: A128075 A128076 A128077 * A128079 A128080 A128081

Keyword

tabl,sign

Author

Gary W. Adamson, Feb 14 2007

Status

approved