A128995 For a number n, let r=n+1, s = the least number greater than r and coprime to nr; n is here if nr-s, rs-n and sn-r are all prime.

3, 4, 5, 6, 9, 13, 14, 15, 19, 20, 26, 32, 35, 36, 42, 55, 68, 88, 89, 93, 118, 145, 155, 169, 172, 174, 186, 234, 259, 330, 356, 384, 405, 488, 494, 495, 530, 569, 594, 608, 660, 715, 726, 746, 763, 779, 825, 863, 1069, 1124, 1143, 1149, 1320, 1342, 1365

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

14 is here because 14x15-17, 15x17-14 and 17x14-15 are all prime.

Crossrefs

Sequence in context: A022884 A105857 A103055 * A293306 A014101 A039035

Adjacent sequences: A128992 A128993 A128994 * A128996 A128997 A128998

Keyword

nonn

Author

J. M. Bergot, Apr 30 2007

Extensions

Edited by Don Reble, Jan 20 2008

Status

approved