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Search: id:A027973
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| A027973 |
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a(n) = T(n,n) + T(n,n+1) + ... + T(n,2n), T given by A027960. |
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+0
4
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| 1, 4, 9, 21, 46, 99, 209, 436, 901, 1849, 3774, 7671, 15541, 31404, 63329, 127501, 256366, 514939, 1033449, 2072676, 4154701, 8324529, 16673534, 33386671, 66837421, 133778524, 267724809, 535721061, 1071881326, 2144473299
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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With a different offset: recurrence: a(-1)=a(0)=1 a(n+2)=a(n+1)+a(n)+2^n; formula: a(n-2) = floor(2^n-PHI^n) - (1-(-1)^n)/2 - Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 02 2002
a(n) = A101220(4, 2, n+1) - A101220(4, 2, n). - Ross La Haye (rlahaye(AT)new.rr.com), Aug 05 2005
a(n)=2a(n-1)+Fibonacci(n+1)-Fibonacci(n-3) for n>=1; a(0)=1. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 29 2006
O.g.f.: -4/(-1+2*x)+(x+3)/(-1+x+x^2). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 23 2007
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MAPLE
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with(combinat): a[0]:=1: for n from 1 to 30 do a[n]:=2*a[n-1]+fibonacci(n+1)-fibonacci(n-3) od: seq(a[n], n=0..30); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 29 2006
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CROSSREFS
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Sequence in context: A048638 A144527 A117880 this_sequence A103040 A084861 A122498
Adjacent sequences: A027970 A027971 A027972 this_sequence A027974 A027975 A027976
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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