A216944 The least odd prime p for which the n-th prime can be written as 3p + q - 3 for some odd prime q.

3, 3, 3, 3, 3, 3, 5, 3, 5, 3, 3, 3, 3, 7, 3, 5, 3, 3, 5, 3, 7, 5, 3, 3, 3, 3, 7, 7, 3, 5, 5, 5, 3, 3, 7, 3, 3, 7, 5, 5, 3, 3, 5, 5, 11, 3, 3, 3, 5, 5, 3, 3, 3, 11, 3, 5, 3, 5, 11, 7, 3, 3, 7, 3, 11, 5, 3, 3, 7, 3, 3, 11, 3, 7, 5, 5, 7, 5, 5, 5, 3, 5, 3, 7, 5, 3, 3

Offset: 5

Author

Marius Coman, Sep 20 2012

Keywords

• nonn

Comments

Conjecture: Any prime >= 11 can be written this way.

Examples

			The corresponding q and prime(n): (5,11), (7,13), (11,17), (13,19), (17,23), (23,29), (19,31), (31,37), (29,41), (37,43), (41,47), (47,53), (53,59), (43,61), (61,67), (67,73), (73,79), (71,83), (83,89), (79,97), (89,101), (97,103), (101,107), (103,109), (107,113), (109,127), (113,131), (131,137), (127,139), (137,149), (139,151), (151,157), (157,163), (149,167), (167,173), (173,179), (163,181), (179,191), (181,193), (191,197), (193,199), (199,211), (211,223), (197,227), (223,229), (227,233), (233,239), (229,241), (239,251), (251,257), (257,263), (263,269), (241,271),  (271,277), (269,281), (277,283), (281,293), (277,307), (293,311), (307,313), (311,317), (313,331), (331,337), (317,347), (337,349), (347,353), (353,359), (349,367), (367,373), (373,379), (353,383), (383,389), (379,397), (389,401), (397,409), (401,419), (409,421), (419,431), (421,433), (433,439), (431,443), (443,449), (439,457), (449,461), (457,463), (461,467), (467,479).
		

Links

• Robert Israel, Table of n, a(n) for n = 5..10000

Programs

Maple

f:= proc(n) local p,q;
  p:= 2;
  while 3*pRobert Israel, Mar 08 2018

PARI

a(n)=my(r=prime(n)+3); forprime(p=3,r\3-1,if(isprime(r-3*p), return(p))) \\ Charles R Greathouse IV, Dec 07 2014

Extensions

New name from Charles R Greathouse IV, Dec 07 2014

Corrected by Charles R Greathouse IV, Dec 07 2014