login
Primes with even number of 1's in binary expansion such that next prime also has even number of 1's.
3

%I #14 Jan 31 2019 08:22:03

%S 3,23,83,139,257,263,277,337,347,349,353,383,467,503,593,683,811,839,

%T 853,887,977,1091,1093,1097,1217,1223,1283,1303,1307,1381,1399,1427,

%U 1429,1433,1487,1499,1511,1553,1601,1613,1619,1723,1811,1847,1871,1879

%N Primes with even number of 1's in binary expansion such that next prime also has even number of 1's.

%H Harvey P. Dale, <a href="/A027701/b027701.txt">Table of n, a(n) for n = 1..1001</a> (offset adapted by _Georg Fischer_, Jan 31 2019)

%t Prime[#]&/@Flatten[Position[Partition[Table[DigitCount[n,2,1],{n,Prime[ Range[300]]}],2,1],_?(EvenQ[First[#]]&&EvenQ[Last[#]]&),{1},Heads-> False]] (* _Harvey P. Dale_, Aug 15 2013 *)

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_.

%E More terms from _Erich Friedman_.

%E Offset changed by _Michel Marcus_, Mar 29 2018