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Search: id:A153793
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| A153793 |
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13 times pentagonal numbers: 13n(3n-1)/2. |
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+0
2
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| 0, 13, 65, 156, 286, 455, 663, 910, 1196, 1521, 1885, 2288, 2730, 3211, 3731, 4290, 4888, 5525, 6201, 6916, 7670, 8463, 9295, 10166, 11076, 12025, 13013, 14040, 15106, 16211, 17355, 18538, 19760, 21021, 22321, 23660, 25038, 26455
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OFFSET
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0,2
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FORMULA
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a(n) = (39n^2 - 13n)/2 = A000326(n)*13.
a(n)=39*n+a(n-1)-65 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009]
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EXAMPLE
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For n=2, a(2)=39*2+0-65=13; n=3, a(3)=39*3+13-65=65; n=4, a(4)=39*4+65-65=156 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009]
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CROSSREFS
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Cf. A000326, A153792.
Sequence in context: A054477 A010820 A022705 this_sequence A067160 A147067 A147075
Adjacent sequences: A153790 A153791 A153792 this_sequence A153794 A153795 A153796
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KEYWORD
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easy,nonn,new
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), Jan 01 2009
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