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Search: id:A045883
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| 0, 1, 3, 9, 23, 57, 135, 313, 711, 1593, 3527, 7737, 16839, 36409, 78279, 167481, 356807, 757305, 1601991, 3378745, 7107015, 14913081, 31224263, 65244729, 136081863, 283348537, 589066695, 1222872633, 2535223751, 5249404473
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Without the initial zero, PSumSIGN transform of A001787. - Michael Somos, Jul 10 2003
Number of rises (drops) in the compositions of n-2 with parts in N.
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LINKS
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S. Heubach and T. Mansour, Counting rises, levels, and drops in compositions
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FORMULA
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G.f.: x/((1+x)(1-2x)^2). a(n)=3a(n-1)-4a(n-3).
Convolution of A001045 and A000079. G.f. : x((1-2x)(1-x-2x^2)). - Paul Barry (pbarry(AT)wit.ie), May 21 2004
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PROGRAM
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(PARI) a(n)=if(n<-1, 0, ((3*n+1)*2^n-(-1)^n)/9)
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CROSSREFS
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Partial sums of A059570, bisection: A014916.
Row sums of triangle A094953.
Sequence in context: A018555 A064551 A005783 this_sequence A133654 A096574 A045650
Adjacent sequences: A045880 A045881 A045882 this_sequence A045884 A045885 A045886
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KEYWORD
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easy,nonn
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AUTHOR
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Edward Early (efedula(AT)mit.edu)
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EXTENSIONS
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Simpler description from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jul 18 2002
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