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 A128078 A002260 * A128064. 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 (list; table; graph; refs; listen; history; text; internal format)
 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 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 are: 1; -1, 4; -1, -2, 9; -1, -2, -3, 16; ... CROSSREFS Cf. A002260, A128064, A128077, A000326. Sequence in context: A279816 A004160 A128077 * A264922 A233528 A084604 Adjacent sequences:  A128075 A128076 A128077 * A128079 A128080 A128081 KEYWORD tabl,sign AUTHOR Gary W. Adamson, Feb 14 2007 STATUS approved

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Last modified March 25 12:11 EDT 2019. Contains 321470 sequences. (Running on oeis4.)