login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A155767
Least prime p such that p - 2n is prime, but not both p-2k and p-2(n-k) are prime for 0 < k < n.
3
2, 5, 11, 11, 31, 29, 31, 61, 59, 31, 127, 233, 61, 127, 101, 61, 223, 233, 139, 277, 311, 149, 613, 359, 227, 331, 449, 163, 547, 521, 251, 919, 983, 179, 571, 353, 563, 1693, 599, 277, 739, 773, 307, 907, 1409, 331, 1399, 1721, 389, 1471, 1721, 853, 2503, 929
OFFSET
0,1
COMMENTS
Does a(n) exist for all n? It appears that a(3n) is less than a(3n-1) and a(3n+1) for all n except 1, 2 and 12.
FORMULA
a(n) = A103147(n) + n = A155766(n) + 2n.
CROSSREFS
Sequence in context: A144573 A062251 A091114 * A079782 A371433 A093554
KEYWORD
nonn
AUTHOR
T. D. Noe, Jan 27 2009
STATUS
approved