login
A079797
Products of two primes p and q such that (p*q)^2 + p^2 - q^2 and (p*q)^2 - p^2 + q^2 are both prime.
1
6, 14, 22, 33, 35, 38, 62, 69, 74, 85, 115, 119, 146, 159, 214, 219, 237, 267, 301, 335, 339, 469, 511, 519, 537, 542, 559, 566, 573, 591, 597, 634, 718, 721, 737, 794, 803, 851, 878, 917, 933, 1003, 1007, 1042, 1059, 1099, 1219, 1226, 1241, 1271, 1294, 1299
OFFSET
1,1
COMMENTS
The two primes generated from p and q are sometimes called flip-flap twin primes. There is probably an infinity of them.
EXAMPLE
a(2) = 14 since (2*7)^2 + 2^2 - 7^2 = 151 and (2*7)^2 - 2^2 + 7^2 = 241 are both primes.
CROSSREFS
Sequence in context: A017137 A211998 A190522 * A093380 A123228 A015832
KEYWORD
easy,nonn
AUTHOR
Olivier Gérard, Feb 19 2003
STATUS
approved