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Search: id:A014107
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| 0, -1, 2, 9, 20, 35, 54, 77, 104, 135, 170, 209, 252, 299, 350, 405, 464, 527, 594, 665, 740, 819, 902, 989, 1080, 1175, 1274, 1377, 1484, 1595, 1710, 1829, 1952, 2079, 2210, 2345, 2484, 2627, 2774, 2925, 3080, 3239, 3402, 3569, 3740, 3915, 4094, 4277
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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a(n) = A033537(n) - 8*n^2; A100035(a(n)) = 2 for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 31 2004
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FORMULA
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A014106(-n)=a(n). - Michael Somos Nov 06 2005
G.f.: x(-1+5x)/(1-x)^3. E.g.f: x(-1+2x)exp(x). - Michael Somos Nov 06 2005
a(n)=A097070(n)/A000108(n-2), n>=2 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Apr 12 2007
a[n]:=2*a[n-1]-a[n-2]-4 seq(-a[n]), n>=0. a[0]:=0: a[1]=1 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 18 2008
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MAPLE
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a:=n->sum(j, j=2..n): seq(a(2*n), n=-1..46); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 30 2007
a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=2*a[n-1]-a[n-2]-4 od: seq(-a[n], n=0..47); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 18 2008
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PROGRAM
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(PARI) a(n)=n*(2*n-3)
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CROSSREFS
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Cf. A100036, A100037, A100038, A100039.
a(n)=A100345(n, n-3) for n>2.
Adjacent sequences: A014104 A014105 A014106 this_sequence A014108 A014109 A014110
Sequence in context: A047883 A042915 A007115 this_sequence A090398 A091941 A093835
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KEYWORD
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sign
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AUTHOR
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njas
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