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1, 4, 14, 46, 150, 494, 1652, 5618, 19430, 68302, 243804, 882578, 3235596, 11994922, 44899568, 169466426, 644127110, 2462746382, 9462555788, 36507525266, 141333313220, 548718227642, 2135480023328, 8327573906426, 32530033219580
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n)=A000984(n)+2*A003462(n) E.g.f. exp(3x)-exp(x)+exp(2x)BesselI_0(2x).
Conjecture: n*(3*n^2-17*n+26)*a(n) +2*(-12*n^3+71*n^2-131*n+60)*a(n-1) +(57*n^3-347*n^2+710*n-480)*a(n-2) -6*(2*n-5)*(3*n^2-11*n+12)*a(n-3)=0. - R. J. Mathar, Nov 12 2012
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EXAMPLE
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a(6) = 1652; 3^6 - 1 + binomial(12,6) = 728 + 924 = 1652.
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MAPLE
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MATHEMATICA
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Table[3^n - 1 + Binomial[2 n, n], {n, 0, 50}] (* Wesley Ivan Hurt, Nov 04 2013 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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