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Search: id:A140674
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| 0, 10, 23, 39, 58, 80, 105, 133, 164, 198, 235, 275, 318, 364, 413, 465, 520, 578, 639, 703, 770, 840, 913, 989, 1068, 1150, 1235, 1323, 1414, 1508, 1605, 1705, 1808, 1914, 2023, 2135, 2250, 2368, 2489, 2613, 2740, 2870, 3003, 3139
(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 + 17*n)/2.
a(n) = 7*n + 3*A000217(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 28 2008
a(n)=3*n+a(n-1)+4 (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+4=10; n=3, a(3)=3*3+10+4=23; a(4)=3*4+23+4=39 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
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MAPLE
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with(finance):seq(add(cashflows([2, k, n], 0 ), k=4..n), n=3..46); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 22 2008
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MATHEMATICA
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s=0; lst={s}; Do[s+=n++ +10; AppendTo[lst, s], {n, 0, 7!, 3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 17 2008]
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CROSSREFS
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Cf. A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140673, A140675.
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: A054095 A125618 A154033 this_sequence A072245 A135277 A156202
Adjacent sequences: A140671 A140672 A140673 this_sequence A140675 A140676 A140677
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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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