A027705 Primes with odd number of 1's in binary expansion such that next prime has even number of 1's.

2, 13, 19, 41, 47, 67, 79, 97, 109, 137, 157, 193, 251, 271, 283, 307, 313, 331, 367, 379, 397, 443, 457, 463, 499, 521, 541, 569, 587, 617, 641, 661, 677, 733, 743, 769, 787, 809, 829, 859, 877, 883, 929, 971, 1009, 1021, 1039, 1051, 1087, 1109, 1129, 1171, 1213, 1231, 1259, 1279, 1291

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:=1000: # to get all terms in the first N primes
Res:= NULL: w:= 0: p:= 0:
for i from 1 to N+1 do
   q:= nextprime(p);
   v:= convert(convert(q, base, 2), `+`) mod 2;
   if w = 1 and v = 0 then Res:= Res, p fi;
   p:= q; w:= v;
od:
Res; # Robert Israel, Dec 29 2016

Crossrefs

Sequence in context: A020601 A298051 A298656 * A296938 A350976 A296199

Adjacent sequences: A027702 A027703 A027704 * A027706 A027707 A027708

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)

Offset changed by Robert Israel, Dec 29 2016

Status

approved