A175320 Positive integers which cannot be represented as half-sums (averages) of two primes with indices that are primes with prime indices.

1, 2, 3, 4, 6, 7, 9, 10, 12, 13, 14, 15, 16, 17, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 85

Offset

1,2

Comments

Appears to be finite with the last term being a(1578727)=161352166. If a(1578728) exists, it is greater than 10^9.

The (apparently) last 19 terms are listed in A175321.

Computed at the suggestion of Jonathan Vos Post.

Links

J. S. Kimberley, Table of n, a(n) for n=1..1578727

Formula

The complement of A175319.

Crossrefs

Cf. A174682.

Sequence in context: A186275 A214857 A362443 * A325597 A001953 A230748

Adjacent sequences: A175317 A175318 A175319 * A175321 A175322 A175323

Keyword

nonn

Author

Jason Kimberley, Apr 04 2010

Status

approved