A147820 Nearest-neighbors of odd primes, divided by 2.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 33, 34, 35, 36, 37, 39, 40, 41, 42, 44, 45, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 63, 64, 65, 66, 68, 69, 70, 74, 75, 76, 78, 79, 81

Offset: 1

Author

Omar E. Pol, Nov 14 2008

Keywords

• easy
• nonn

Crossrefs

Cf. A134926, A134933, A147819.

Programs

Mathematica

Union[Flatten[{(#-1)/2,(#+1)/2}&/@Prime[Range[2,40]]]] (* Harvey P. Dale, Oct 19 2011 *)

Formula

a(n) = A147819(n)/2.