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Search: id:A050509
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| A050509 |
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House numbers (version 2): a(n)=(n+1)^3 + (n+1)*sum(i,i=0..n). |
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+0
2
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| 1, 10, 36, 88, 175, 306, 490, 736, 1053, 1450, 1936, 2520, 3211, 4018, 4950, 6016, 7225, 8586, 10108, 11800, 13671, 15730, 17986, 20448, 23125, 26026, 29160, 32536, 36163, 40050, 44206, 48640, 53361, 58378, 63700, 69336, 75295, 81586, 88218
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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a(n)=A000578(n+1)+(n+1)*A000217(n)
Also as a(n)=(1/6)*(9*n^3-3*n^2), n>0: structured pentagonal prism numbers (Cf. A100177 - structured prisms; A100145 for more on structured numbers). - James A. Record (james.record(AT)gmail.com), Nov. 7, 2004.
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FORMULA
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a(n)= (1/2) *(3*n+2)*(n+1)^2
sum ((j+n+1)*(n+1),j=0..n). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 01 2006
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EXAMPLE
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..... * ... *
a(2)=* * + * * = 10
.... * * . * *
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CROSSREFS
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A051662, A000578, A000217.
Sequence in context: A072517 A033585 A118629 this_sequence A118415 A051959 A117327
Adjacent sequences: A050506 A050507 A050508 this_sequence A050510 A050511 A050512
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 28 1999
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