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Search: id:A067998
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| 0, -1, 0, 3, 8, 15, 24, 35, 48, 63, 80, 99, 120, 143, 168, 195, 224, 255, 288, 323, 360, 399, 440, 483, 528, 575, 624, 675, 728, 783, 840, 899, 960, 1023, 1088, 1155, 1224, 1295, 1368, 1443, 1520, 1599, 1680, 1763, 1848, 1935, 2024, 2115, 2208, 2303, 2400, 2499, 2600, 2703, 2808, 2915, 3024, 3135, 3248, 3363
(list; graph; listen)
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OFFSET
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0,4
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FORMULA
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a(n) = A005563(n-2) = A005563(-n) = A000290(n-1)-1
G.f.: x(3x-1)/(1-x)^3; E.g.f.: e^x(x^2-x); - Paul Barry (pbarry(AT)wit.ie), Mar 27 2007
a(n)=2*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)=2*2+0-5=-1; n=3, a(3)=2*3-1-5=0; n=4, a(4)=2*4+0-5=3 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
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MAPLE
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a:=n->sum(binomial(n, 1), j=3..n): seq(a(n), n=0..59); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 12 2007
a[0]:=0:a[1]:=1:for n from 2 to 63 do a[n]:=2*a[n-1]-a[n-2]-2 od: seq(-a[n], n=1..63); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 18 2008
with(combinat, fibonacci):seq(fibonacci(3, i)-2, i=-1..58); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 20 2008
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MATHEMATICA
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Table[ n^2 - 2*n, {n, 0, 60} ]
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CROSSREFS
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Essentially the same as A005563.
Sequence in context: A132411 A147998 A164003 this_sequence A060615 A022451 A080181
Adjacent sequences: A067995 A067996 A067997 this_sequence A067999 A068000 A068001
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KEYWORD
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easy,sign,new
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AUTHOR
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George E. Antoniou (george.antoniou(AT)montclair.edu), Feb 06 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 08 2002
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