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A128078
2
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, ...).
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
KEYWORD
tabl,sign
AUTHOR
Gary W. Adamson, Feb 14 2007
STATUS
approved