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Search: id:A129654
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| A129654 |
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Number of different ways to represent n as general polygonal number P(m,r) = 1/2*r*((m-2)*r-(m-4)) = n>1, for m,r>1. |
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+0
2
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| 1, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 4, 3, 2, 3, 2, 2, 4, 3, 2, 3, 3, 2, 3, 4, 2, 3, 2, 2, 3, 3, 3, 5, 2, 2, 3, 3, 2, 3, 2, 2, 5, 3, 2, 3, 3, 2, 4, 3, 2, 3, 4, 2, 3, 3, 2, 3, 2, 2, 3, 4, 3, 5, 2, 2, 3, 4, 2, 3, 2, 2, 4, 3, 2, 4, 2, 2, 5, 3, 2, 3, 3, 2, 3, 3, 2, 3, 4, 3, 3, 3, 3, 4, 2, 2, 3, 4, 2, 3, 2, 2, 5, 3
(list; graph; listen)
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OFFSET
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2,2
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COMMENT
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The indices k of the first appearance of number n in a(k) are listed in A063778(n) = {2,3,6,15,36,225,...} = Least number k>1 such that k could be represented in n different ways as general m-gonal number P(m,r) = 1/2*r*((m-2)*r-(m-4)).
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LINKS
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Eric Weisstein, Link to a section of The World of Mathematics, Polygonal Number.
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EXAMPLE
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a(6) = 3 because 6 = P(2,6) = P(3,3) = P(6,2).
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CROSSREFS
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Cf. A063778.
Sequence in context: A160493 A091322 A053760 this_sequence A138789 A116504 A104011
Adjacent sequences: A129651 A129652 A129653 this_sequence A129655 A129656 A129657
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KEYWORD
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nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Apr 27 2007
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