A134197 Primes that occur in A126990 twice.

3, 7, 13, 23, 31, 47, 61, 73, 89, 103, 113, 131, 139, 151, 167, 181, 193, 199, 233, 241, 271, 293, 317, 337, 359, 389, 409, 421, 433, 449, 467, 491, 509, 523, 547, 577, 601, 619, 647, 661, 691, 709, 743, 761, 773, 797, 811, 823, 839, 863, 887, 919, 941, 953

Offset: 1

Author

Artur Jasinski, Oct 13 2007

Keywords

• nonn

Comments

It seems, as tested up to prime(100000), that triplicates of primes do not occur in A126990, so this sequence stays the same if defined as either "... in A126990 exactly twice" or "... in A126990 at least twice." - Michel Marcus and R. J. Mathar, Nov 07 2013

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A126990, A134196.

Programs

PARI

lista(nn) = {last = A126990(1); for (n=2, nn, new = A126990(n); if (new == last, print1(new, ", ")); last = new;);} \\ Michel Marcus, Nov 07 2013

Extensions

More terms from Michel Marcus, Nov 07 2013