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Search: id:A069129
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| A069129 |
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Centered 16-gonal numbers. |
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+0
17
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| 1, 17, 49, 97, 161, 241, 337, 449, 577, 721, 881, 1057, 1249, 1457, 1681, 1921, 2177, 2449, 2737, 3041, 3361, 3697, 4049, 4417, 4801, 5201, 5617, 6049, 6497, 6961
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also, sequence found by reading the line from 1, in the direction 1, 17,..., in the square spiral whose vertices are the triangular numbers A000217. Opposite numbers to the members of A139098 in the same spiral. - Omar E. Pol (info(AT)polprimos.com), Apr 26 2008
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LINKS
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E. Weisstein, Centered Polygonal Numbers
Index entries for sequences related to centered polygonal numbers
O. E. Pol, Determinacion geometrica de los numeros primos y perfectos.
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FORMULA
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a(n) = 8n^2 - 8n + 1
a(n) = A035008(n-1) + 1. - Omar E. Pol (info(AT)polprimos.com), Apr 26 2008
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EXAMPLE
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a(5) = 161 because 8*5^2 - 8*5 + 1 = 200 - 40 + 1 = 161.
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CROSSREFS
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Cf. A005448, A001844, A005891, A003215, A069099.
Cf. A000217, A035008, A139098.
Adjacent sequences: A069126 A069127 A069128 this_sequence A069130 A069131 A069132
Sequence in context: A031122 A051869 A029487 this_sequence A124710 A113867 A049737
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Terrel Trotter, Jr. (ttrotter(AT)telesal.net), Apr 07 2002
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