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A135482
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a(n) = (1/4)*Sum_{j=1..n} 2^prime(j).
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2
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0, 1, 3, 11, 43, 555, 2603, 35371, 166443, 2263595, 136481323, 673352235, 35033090603, 584788904491, 2783812160043, 37968184248875, 2289767997934123, 146404956073789995, 722865708377213483, 37616353855796316715, 627912164214501968427, 2989095405649324575275
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OFFSET
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0,3
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LINKS
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FORMULA
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MAPLE
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MATHEMATICA
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Accumulate[Table[Floor[2^i/4], {i, Prime[Range[20]]}]] (* Harvey P. Dale, Dec 05 2013 *)
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PROG
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(Magma) [&+[2^(NthPrime(k)-2): k in [1..n]]: n in [1..25]]; // Bruno Berselli, Sep 24 2015
(PARI) a(n) = sum(k=1, n, 2^prime(k))/4; \\ Michel Marcus, Oct 15 2016
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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