Generalized pentagonal numbers: n*(3*n-1)/2, n=0, +- 1, +- 2, +- 3,.... 0, 1, 2, 5, 7, 12, 15, 22, 26, 35, 40, 51, 57, 70, 77, 92, 100, 117, 126, 145, 155, 176
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