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0, 1, 13, 133, 1261, 11605, 105469, 953317, 8596237, 77431669, 697147165, 6275373061, 56482551853, 508359743893, 4575304803901, 41178011670565, 370603178776909, 3335432903959477, 30018913315504477, 270170288559017029
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OFFSET
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0,3
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COMMENTS
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a(n) is also the coefficient of x^(n-1) in the bivariate Fibonacci polynomials F(n)(x,y)=xF(n-1)(x,y)+yF(n-2)(x,y),F(0)(x,y)=0,F(1)(x,y)=1, when we write 13x for x and -36x^2 for y. - Mario Catalani (mario.catalani(AT)unito.it), Dec 09 2002
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LINKS
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Table of n, a(n) for n=0..19.
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FORMULA
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G.f.: x/((1-4*x)*(1-9*x)). a(n)=13*a(n-1)-36*a(n-2).
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MATHEMATICA
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Join[{a=0, b=1}, Table[c=13*b-36*a; a=b; b=c, {n, 60}]](*and/or*)f[n_]:=(9^n-4^n)/5; f[Range[0, 60]] (*From Vladimir Joseph Stephan Orlovsky, Feb 01 2011*)
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PROG
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(PARI) a(n)=(9^n-4^n)/5
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CROSSREFS
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A016153(n)=A015441(2*n)
Sequence in context: A199144 A198664 A081042 * A187732 A031138 A097166
Adjacent sequences: A016150 A016151 A016152 * A016154 A016155 A016156
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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