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A221858
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a(1)=2, a(2)=3, for n>=3, a(n) is the n-th number which is obtained by application of Eratosthenes-like sieve (with removing 1's) to sequence: odd part of digit sum of 2^m, m>=1.
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12
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2, 3, 7, 5, 11, 13, 19, 29, 31, 41, 37, 43, 47, 61, 59, 67, 71, 23, 17, 73, 79, 89, 109, 103, 53, 107, 113, 139, 151, 127, 137, 83, 167, 173, 181, 191, 101, 193, 223, 233, 211, 199, 229, 251, 239, 281, 277, 241, 131, 269, 263, 283, 313, 311, 349, 163, 317, 337, 331, 307
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OFFSET
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1,1
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COMMENTS
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We conjecture that every term is prime;
moreover, we conjecture that the sequence is a permutation of the sequence of all primes.
For comparison, if in the definition we replace 2^m with 13^m, then we obtain a sequence containing 25. - Vladimir Shevelev, Dec 07 2014
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LINKS
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MATHEMATICA
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Flatten[{{2, 3}, DeleteDuplicates[Select[Map[#/(2^IntegerExponent[#, 2])&[Total[IntegerDigits[2^#]]]&, Range[3, 300]], PrimeQ]]}] (* Peter J. C. Moses, Apr 25 2013 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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