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Search: id:A077864
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| A077864 |
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Expansion of (1-x)^(-1)/(1-x-2*x^2-x^3). |
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+0
2
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| 1, 2, 5, 11, 24, 52, 112, 241, 518, 1113, 2391, 5136, 11032, 23696, 50897, 109322, 234813, 504355, 1083304, 2326828, 4997792, 10734753, 23057166, 49524465, 106373551, 228479648, 490751216, 1054084064, 2264066145, 4862985490, 10445201845, 22435238971, 48188628152
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Diagonal sums of triangle using cumulative sums of odd-indexed rows of Pascal's triangle (cf. A020988). - Paul Barry (pbarry(AT)wit.ie), May 18 2003
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FORMULA
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a(0)=1, a(1)=2, a(2)=5, a(3)=11, a(n)=2*a(n-1)+a(n-2)-a(n-3)-a(n-4) for n>3 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 25 2006
a(n) = term (4,1) in the 4x4 matrix [1,1,0,0; 2,0,1,0; 1,0,0,0; 1,0,0,1]^(n+1). - Alois P. Heinz (heinz(AT)hs-heilbronn.de), Jul 24 2008
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MAPLE
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a := n -> (Matrix([[1, 1, 0, 0], [2, 0, 1, 0], [1, 0, 0, 0], [1, 0, 0, 1]])^(n+1))[4, 1]; seq (a(n), n=0..50); - Alois P. Heinz (heinz(AT)hs-heilbronn.de), Jul 24 2008
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CROSSREFS
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Sequence in context: A027934 A134389 A111297 this_sequence A052980 A110513 A018115
Adjacent sequences: A077861 A077862 A077863 this_sequence A077865 A077866 A077867
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Nov 17 2002
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