A218851 a(n) = 2*floor((n + sin(n)/(2*sin(1/2))) * log(n)) + 1.

1, 5, 7, 9, 13, 21, 29, 37, 41, 43, 47, 57, 69, 79, 85, 87, 91, 99, 113, 125, 133, 135, 139, 147, 161, 175, 185, 189, 191, 197, 211, 225, 239, 243, 245, 251, 263, 279, 293, 301, 303, 307, 317, 333, 349, 359, 363, 365, 373, 389, 407, 419, 425, 427, 433, 447

Offset

1,2

Comments

This sequence of odd integers mimics the prime numbers and more specifically it is conjectured a(n) satisfies an analog of the k-tuple conjecture (see link) with similar heuristic asymptotic formulas.

Links

Table of n, a(n) for n=1..56.

Benoit Cloitre, A k-tuple conjecture for an explicit sequence

Mathematica

Table[2*Floor[(n + Sin[n]/(2*Sin[1/2]))*Log[n]] + 1, {n, 60}] (* T. D. Noe, Nov 08 2012 *)

Prog

(PARI) a(n)=2*floor((n+sin(n)/2/sin(1/2))*log(n))+1

Crossrefs

Sequence in context: A039504 A097280 A155732 * A211184 A350666 A327307

Adjacent sequences: A218848 A218849 A218850 * A218852 A218853 A218854

Keyword

nonn

Author

Benoit Cloitre, Nov 07 2012

Status

approved