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Search: id:A120071
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| 0, 21, 44, 69, 96, 125, 156, 189, 224, 261, 300, 341, 384, 429, 476, 525, 576, 629, 684, 741, 800, 861, 924, 989, 1056, 1125, 1196, 1269, 1344, 1421, 1500, 1581, 1664, 1749, 1836, 1925, 2016, 2109, 2204, 2301
(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)= (n+10)^2-10^2 = n*(n+20), n>=0.
G.f.: x*(21-19*x)/(1-x)^3.
a(n)=2*n+a(n-1)+17 (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)=2*2+0+17=21; n=3, a(3)=2*3+21+17=44; n=4, a(4)=2*4+44+17=69 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
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MAPLE
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seq(sum(4*k-n, k=7..n), n=6..51); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 17 2008
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MATHEMATICA
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s=0; lst={}; Do[s+=n; AppendTo[lst, s], {n, 21, 6!, 2}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 26 2009]
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CROSSREFS
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a(n-10), n>=11, tenth column (used for the n=10 series of the hydrogen atom) of triangle A120070.
For n*(n+18) see A098850.
Cf. A001477, A098849, A132760, A120061, A132765.
Cf. A132760, A132761, A132762, A098849, A098850, A005563, A028552, A028347, A028557, A028560, A028563, A028566, A028569, A098603, A098847, A132759, A098848 [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 26 2009]
Sequence in context: A041878 A041880 A063319 this_sequence A003857 A099468 A063500
Adjacent sequences: A120068 A120069 A120070 this_sequence A120072 A120073 A120074
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KEYWORD
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nonn,easy,new
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Jul 20 2006
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