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 A280872 Primes that have exactly 7 zeros and 7 ones in their binary expansion. 2
 8287, 8311, 8317, 8423, 8429, 8527, 8539, 8563, 8599, 8627, 8629, 8647, 8677, 8681, 8689, 8783, 8807, 8819, 8821, 8861, 8933, 8999, 9011, 9013, 9043, 9049, 9059, 9109, 9137, 9157, 9161, 9277, 9319, 9323, 9337, 9371, 9397, 9419, 9421, 9433, 9511, 9547, 9613, 9619 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS K. D. Bajpai, Table of n, a(n) for n = 1..189 EXAMPLE 8287 is in the sequence because it is a prime and its binary expansion 10000001011111 contains exactly 7 zeros and 7 ones. 9161 is in the sequence because it is a prime and its binary expansion 10001111001001 contains exactly 7 zeros and 7 ones. MAPLE select(t -> isprime(t) and convert(convert(t, base, 2), `+`)=7, [seq(i, i=2^13+1..2^14-1, 2)]); # Robert Israel, Jan 09 2017 MATHEMATICA Select[Prime[Range[50000]], Count[IntegerDigits[#, 2], 0] == Count[IntegerDigits[#, 2], 1] == 7 &] Select[FromDigits[#, 2]&/@(Join[{1}, #]&/@Permutations[ {1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0}]), PrimeQ]//Union (* Harvey P. Dale, May 10 2019 *) CROSSREFS Cf. A000040, A007088, A014311, A066196. Sequence in context: A054215 A031589 A031769 * A329342 A237948 A250991 Adjacent sequences:  A280869 A280870 A280871 * A280873 A280874 A280875 KEYWORD nonn,base,fini,full AUTHOR K. D. Bajpai, Jan 09 2017 STATUS approved

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Last modified September 23 09:03 EDT 2020. Contains 337298 sequences. (Running on oeis4.)