login
A172238
Primes p such that either p+5/2+-3/2 is prime.
0
2, 3, 7, 13, 19, 37, 43, 67, 79, 97, 103, 109, 127, 163, 193, 223, 229, 277, 307, 313, 349, 379, 397, 439, 457, 463, 487, 499, 613, 643, 673, 739, 757, 769, 823, 853, 859, 877, 883, 907, 937, 967, 1009, 1087, 1093, 1213, 1279, 1297, 1303, 1423, 1429, 1447, 1483
OFFSET
1,1
COMMENTS
Two together with primes p such that p and p+4 are both primes.
EXAMPLE
a(1)=2 because 2+5/2-3/2=3(prime) and 2+5/2+3/2=6(nonprime); a(2)=3 because 3+5/2-3/2=4(nonprime) and 3+5/2+3/2=7(prime).
CROSSREFS
Cf. A023200.
Sequence in context: A130272 A331948 A342529 * A319496 A038940 A019383
KEYWORD
nonn
AUTHOR
EXTENSIONS
Entries checked by R. J. Mathar, May 02 2010
STATUS
approved