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Search: id:A140675
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| 0, 11, 25, 42, 62, 85, 111, 140, 172, 207, 245, 286, 330, 377, 427, 480, 536, 595, 657, 722, 790, 861, 935, 1012, 1092, 1175, 1261, 1350, 1442, 1537, 1635, 1736, 1840, 1947, 2057, 2170, 2286, 2405, 2527, 2652, 2780, 2911, 3045, 3182
(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)=(3*n^2 + 19*n)/2.
a(n)=3*n+a(n-1)+5 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
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EXAMPLE
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For n=2, a(2)=3*2+0+5=11; n=3, a(3)=3*3+11+5=25; n=4, a(4)=3*4+25+5=42 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
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MATHEMATICA
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s=0; lst={s}; Do[s+=n++ +11; AppendTo[lst, s], {n, 0, 7!, 3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 19 2008]
Table[Sum[i + n - 3, {i, 7, n}], {n, 6, 52}] [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 11 2009]
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CROSSREFS
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Cf. A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140673, A140674.
The generalized pentagonal numbers b*n+3*n*(n-1)/2, for b = 1 through 12, form sequences A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140673, A140674, A140675, A151542.
Sequence in context: A084547 A125868 A031025 this_sequence A161532 A118648 A105270
Adjacent sequences: A140672 A140673 A140674 this_sequence A140676 A140677 A140678
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KEYWORD
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easy,nonn
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), May 22 2008
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