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Search: id:A100175
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| A100175 |
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Structured triakis tetrahedral numbers (vertex structure 4). |
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+0
3
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| 1, 8, 30, 76, 155, 276, 448, 680, 981, 1360, 1826, 2388, 3055, 3836, 4740, 5776, 6953, 8280, 9766, 11420, 13251, 15268, 17480, 19896, 22525, 25376, 28458, 31780, 35351, 39180, 43276, 47648
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Equals binomial transform of [1, 7, 15, 9, 0, 0, 0,...] where (1, 7, 15, 9) = row 3 of triangle A038763. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jul 19 2008
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FORMULA
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a(n)=(1/6)*(9*n^3-9*n^2+6*n)
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CROSSREFS
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Cf. A000578 = alternate vertex; A100145 for more on structured numbers.
Cf. A038763.
Adjacent sequences: A100172 A100173 A100174 this_sequence A100176 A100177 A100178
Sequence in context: A004639 A131769 A055832 this_sequence A063489 A002417 A126858
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KEYWORD
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easy,nonn
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AUTHOR
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James A. Record (james.record(AT)gmail.com). Nov 07, 2004.
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