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A075090
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Even perfect powers: numbers of the form (2*m)^k for some m>=1 and k>=2.
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9
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4, 8, 16, 32, 36, 64, 100, 128, 144, 196, 216, 256, 324, 400, 484, 512, 576, 676, 784, 900, 1000, 1024, 1156, 1296, 1444, 1600, 1728, 1764, 1936, 2048, 2116, 2304, 2500, 2704, 2744, 2916, 3136, 3364, 3600, 3844, 4096, 4356, 4624, 4900, 5184, 5476, 5776, 5832
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OFFSET
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1,1
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LINKS
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FORMULA
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Sum_{n>=1} 1/a(n) = -Sum_{k>=2} mu(k)*zeta(k)/2^k = 0.5854268109... - Amiram Eldar, Dec 19 2020
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MAPLE
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q:= n-> n::even and igcd(seq(i[2], i=ifactors(n)[2]))>1:
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MATHEMATICA
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Take[Union[Flatten[Table[a^b, {a, 2, 100, 2}, {b, 2, 15}]]], 50] (* Alonso del Arte, Nov 22 2011 *)
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PROG
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(Haskell)
a075090 n = a075090_list !! (n-1)
(PARI) isok(m) = !(m%2) && ispower(m); \\ Michel Marcus, May 03 2022
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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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EXTENSIONS
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STATUS
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approved
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