A107323 - OEIS

A107323

If n-th prime is 6m-1, then a(n) = 6m+1. If n-th prime is 6m+1, then a(n) = 6m-1.

7, 5, 13, 11, 19, 17, 25, 31, 29, 35, 43, 41, 49, 55, 61, 59, 65, 73, 71, 77, 85, 91, 95, 103, 101, 109, 107, 115, 125, 133, 139, 137, 151, 149, 155, 161, 169, 175, 181, 179, 193, 191, 199, 197, 209, 221, 229, 227, 235, 241, 239, 253, 259, 265, 271, 269, 275, 283

(list; graph; refs; listen; history; text; internal format)

OFFSET

3,1

LINKS

Michael De Vlieger, Table of n, a(n) for n = 3..10000

FORMULA

a(n) = A000040(n) +2*A173950(n). - R. J. Mathar, Dec 17 2017

MAPLE

a:=proc(n) if ithprime(n) mod 6 = 5 then ithprime(n)+2 elif ithprime(n) mod 6 = 1 then ithprime(n)-2 else 0 fi end: seq(a(n), n=3..68); # Emeric Deutsch, Jun 19 2005

MATHEMATICA

Map[If[Mod[#, 6] == 5, # + 2, # - 2] &, Prime@ Range[3, 60]] (* Michael De Vlieger, Sep 04 2017 *)

CROSSREFS

Sequence in context: A176672 A107471 A332768 * A265794 A265818 A046557

Adjacent sequences: A107320 A107321 A107322 * A107324 A107325 A107326

KEYWORD

nonn

AUTHOR

Leroy Quet, May 21 2005

EXTENSIONS

More terms from Emeric Deutsch, Jun 19 2005

STATUS

approved