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Search: id:A153795
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| A153795 |
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5 times octagonal numbers: 5n(3n-2). |
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+0
1
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| 0, 5, 40, 105, 200, 325, 480, 665, 880, 1125, 1400, 1705, 2040, 2405, 2800, 3225, 3680, 4165, 4680, 5225, 5800, 6405, 7040, 7705, 8400, 9125, 9880, 10665, 11480, 12325, 13200, 14105, 15040, 16005, 17000, 18025, 19080, 20165, 21280
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n) = 15n^2 - 10n = A000567(n)*5.
a(n)=30*n+a(n-1)-55 (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)=30*2+0-55=5; n=3, a(3)=30*3+5-55=40; n=4, a(4)=30*4+40-55=105 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009]
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MATHEMATICA
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s=0; lst={s}; Do[s+=n; AppendTo[lst, s], {n, 5, 8!, 30}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 03 2009]
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CROSSREFS
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Cf. A000567, A153794, A153796.
Sequence in context: A118991 A156378 A029538 this_sequence A015874 A027264 A025214
Adjacent sequences: A153792 A153793 A153794 this_sequence A153796 A153797 A153798
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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 20 2009
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