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A027702
Numbers k such that the k-th prime has an even number of 1's in binary expansion and the (k+1)st prime also has an even number of 1's.
3
2, 9, 23, 34, 55, 56, 59, 68, 69, 70, 71, 76, 91, 96, 108, 124, 141, 146, 147, 154, 165, 182, 183, 184, 199, 200, 208, 213, 214, 221, 222, 225, 226, 227, 236, 239, 240, 245, 252, 255, 256, 269, 280, 283, 286, 289, 290, 291, 292, 327, 339, 355, 356, 359, 365, 393, 396, 397, 406, 414, 419, 420
OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[1000], EvenQ[DigitCount[Prime[ # ], 2][[1]]] && EvenQ[DigitCount[Prime[ # + 1], 2][[1]]] &] (* Stefan Steinerberger, Apr 21 2006 *)
PROG
(PARI) is(n)=my(p=prime(n)); hammingweight(p)%2==0 && hammingweight(nextprime(p+1))%2==0 \\ Charles R Greathouse IV, Mar 29 2013
CROSSREFS
Sequence in context: A368626 A032149 A032054 * A051897 A209294 A294870
KEYWORD
nonn
EXTENSIONS
More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)
STATUS
approved