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A062709
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a(n) = 2^n + 3.
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28
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4, 5, 7, 11, 19, 35, 67, 131, 259, 515, 1027, 2051, 4099, 8195, 16387, 32771, 65539, 131075, 262147, 524291, 1048579, 2097155, 4194307, 8388611, 16777219, 33554435, 67108867, 134217731, 268435459, 536870915, 1073741827, 2147483651, 4294967299, 8589934595, 17179869187
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OFFSET
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0,1
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COMMENTS
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Written in binary a(n) is 1000...00011 for n > 1.
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LINKS
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FORMULA
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G.f.: (4 - 7*x)/((1 - 2*x)*(1 - x)).
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EXAMPLE
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a(3) = 2^3 + 3 = 8 + 3 = 11.
a(4) = 2^4 + 3 = 16 + 3 = 19.
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MATHEMATICA
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NestList[2 * # - 3 &, 4, 20] (* Zak Seidov, Mar 28 2015 *)
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PROG
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(Sage) [gaussian_binomial(n, 1, 2)+4 for n in range(0, 32)] # Zerinvary Lajos, May 31 2009
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CROSSREFS
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Primes in this sequence are A057733.
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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