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A095934
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G.f.: (1-x)^2/(1-5*x+3*x^2).
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2
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1, 3, 13, 56, 241, 1037, 4462, 19199, 82609, 355448, 1529413, 6580721, 28315366, 121834667, 524227237, 2255632184, 9705479209, 41760499493, 179686059838, 773148800711, 3326685824041, 14313982718072, 61589856118237, 265007332436969, 1140267093830134
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OFFSET
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0,2
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COMMENTS
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a(n) is the number of generalized compositions of n when there are i+2 different types of i, (i=1,2,...). [From Milan Janjic, Sep 24 2010]
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REFERENCES
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P. J. Cameron, Some sequences of integers, Discrete Math., 75 (1989), 89-102; also in "Graph Theory and Combinatorics 1988", ed. B. Bollobas, Annals of Discrete Math., 43 (1989), 89-102.
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LINKS
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Table of n, a(n) for n=0..24.
Index entries for sequences related to linear recurrences with constant coefficients
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FORMULA
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a(n+2) = 5a(n+1) - 3a(n) (n >= 1); a(0) = 1, a(1) = 3, a(2) = 13.
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PROG
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(PARI) a(n)=polcoeff((1-x)^2/(1-5*x+3*x^2)+x*O(x^n), n)
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CROSSREFS
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Cf. A003480, A010903, A010920; equals A095939 + A095940.
Sequence in context: A081952 A010903 A010920 * A151220 A151221 A020515
Adjacent sequences: A095931 A095932 A095933 * A095935 A095936 A095937
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Jul 13 2004
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STATUS
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approved
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