A174215 First differences of A174214.

2, 1, 1, 1, 1, 6, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 5, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 31, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset: 9

Author

Vladimir Shevelev, Mar 12 2010

Keywords

• nonn
• easy

Comments

If a(n) is odd, then it is 1 or prime; if a(n) is even, then 2+a(n)/2 is prime.

Links

• V. Shevelev, Theorems on twin primes-dual case, arXiv:0912.4006

Crossrefs

Cf. A167495, A166945, A174214

Formula

a(n) = A174214(n+1)-A174214(n).

Extensions

Terms corrected, using the Mathar-Layman corrections of A174214, by Vladimir Shevelev, Mar 26 2010