A086519 a(n) is the least prime not already used such that (a(n)+a(n-1))/2 is prime.

3, 7, 19, 43, 31, 103, 151, 67, 79, 127, 199, 163, 139, 223, 331, 211, 271, 283, 379, 367, 307, 439, 487, 607, 547, 499, 643, 571, 523, 619, 463, 631, 691, 727, 739, 883, 823, 751, 787, 859, 907, 811, 1063, 919, 1123, 1051, 967, 1171, 1087, 991, 1471, 1291

Offset

0,1

Comments

Second term onwards every prime == 1 (mod 6). Conjecture: every prime of the type 6k+1 is a member.

After the first term, every member = 7 (mod 12). Conjecture: every prime of the form 12k+7 is a member. - David Wasserman, Mar 11 2005

Links

Table of n, a(n) for n=0..51.

Crossrefs

Cf. A086522.

Sequence in context: A292775 A282024 A356617 * A090689 A145476 A374841

Adjacent sequences: A086516 A086517 A086518 * A086520 A086521 A086522

Keyword

nonn

Author

Amarnath Murthy, Jul 30 2003

Extensions

More terms from David Wasserman, Mar 11 2005

Status

approved