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A027703
Primes with even number of 1's in binary expansion such that next prime has odd number of 1's.
2
5, 17, 29, 43, 53, 71, 89, 101, 113, 149, 163, 197, 269, 281, 293, 311, 317, 359, 373, 389, 401, 449, 461, 479, 509, 523, 547, 571, 599, 619, 643, 673, 691, 739, 751, 773, 797, 821, 857, 863, 881, 907, 937, 983, 1013, 1031, 1049, 1061, 1103, 1117, 1151
OFFSET
1,1
LINKS
FORMULA
a(n) = prime(A027704(n)). - Michel Marcus, Mar 29 2018
MATHEMATICA
c[ n_ ] := OddQ[ Count[ IntegerDigits[ n, 2 ], 1 ] ]; Map[ Prime, Select[ Range[ 300 ], Not[ c[ Prime[ # ] ] ]&&c[ Prime[ #+1 ] ]& ] ]
Prime[#]&/@SequencePosition[Table[If[EvenQ[DigitCount[n, 2, 1]], 1, 0], {n, Prime[ Range[200]]}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 03 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Erich Friedman.
Offset changed by Michel Marcus, Mar 29 2018
STATUS
approved