A126556 Arithmetic mean of two consecutive prime interprimes of second order: interprimes of third order.

734, 2825, 5957, 10305, 13932, 15830, 18825, 25084, 30205, 32121, 34901, 40640, 47984, 70842, 102897, 120165, 125973, 130250, 138924, 145480, 148894, 154236, 161676, 167730, 174737, 180632, 183077, 191253, 210375, 224327, 232817, 246285

Offset: 1

Author

Artur Jasinski, Dec 27 2006

Keywords

• nonn

Comments

For primes in this sequence (prime interprimes of third order) see A126557.

Links

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

Crossrefs

Cf. A006562 (balanced primes), A024675 (interprimes), A126554 (interprimes of second order), A126555 (prime interprimes of second order).

Programs

PARI

{m=250000;a=0;g=0;p=2;q=3;r=5;while(r<=m,if((p+r)/2==q,if(a>0,b=(a+q)/2;if(isprime(b),if(g>0,print1(h=(g+b)/2,","));g=b));a=q);p=q;q=r;r=nextprime(r+1))} \\ Klaus Brockhaus, Jan 11 2007

Formula

a(n) = (A126555(n)+A126555(n+1))/2.

Extensions

Edited by Klaus Brockhaus, Jan 11 2007