login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A027705 Primes with odd number of 1's in binary expansion such that next prime has even number of 1's. 4
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 (list; graph; refs; listen; history; text; internal format)
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 A296199 A121181

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 00:32 EST 2019. Contains 329871 sequences. (Running on oeis4.)