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A005367
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a(n) = 2*(2^n + 1)*(2^(n+1) - 1).
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3
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4, 18, 70, 270, 1054, 4158, 16510, 65790, 262654, 1049598, 4196350, 16781310, 67117054, 268451838, 1073774590, 4295032830, 17180000254, 68719738878, 274878431230, 1099512676350, 4398048608254, 17592190238718, 70368752566270, 281474993487870, 1125899940397054
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: 2*(2 - 5*x)/((1 - x)*(1 - 2*x)*(1 - 4*x)). - Ilya Gutkovskiy, Feb 24 2017
E.g.f.: 2*exp(x)*(2*exp(3*x) + exp(x) - 1).
a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3). (End)
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MATHEMATICA
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Table[2*(2^n + 1)*(2^(n + 1) - 1), {n, 0, 50}] (* G. C. Greubel, Oct 21 2017 *)
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PROG
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(PARI) for(n=0, 50, print1(2*(2^n + 1)*(2^(n + 1) - 1), ", ")) \\ G. C. Greubel, Oct 21 2017
(Magma) [2*(2^n + 1)*(2^(n + 1) - 1): n in [0..50]]; // G. C. Greubel, Oct 21 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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