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A076265
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a(n) = Product_{i=1..n} prime(i)^prime(i).
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11
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OFFSET
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1,1
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COMMENTS
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Denominator of Sum_{i=1..n} 1/(p(i)^p(i)), where p(i) = i-th prime. The numerators are in A117579. E.g., 1/4, 31/108, 96983/337500, 79870008269/277945762500, ... - Jonathan Vos Post, Mar 29 2006
Equally, denominator of Sum_{k=1..n}(-1)^(k+1) * 1/p(k)^p(k), where p(k) = prime(k). - Alexander Adamchuk, Aug 22 2006
C = Sum_{k>=1} (-1)^(k+1)/(prime(k)^prime(k)) = 1/2^2 - 1/3^3 + 1/5^5 - 1/7^7 + 1/11^11 - 1/13^13 + ... A122147 is the decimal expansion of C = 0.213281748700785698255627... - Alexander Adamchuk, Aug 22 2006
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LINKS
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FORMULA
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EXAMPLE
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MATHEMATICA
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Table[Denominator[Sum[1/Prime[k]^Prime[k], {k, 1, n}]], {n, 1, 10}] (* Alexander Adamchuk, Aug 22 2006 *)
Denominator[Accumulate[1/#^#&/@Prime[Range[10]]]] (* Harvey P. Dale, Jan 24 2013 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,frac,easy,changed
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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