A039641 Fixed point of "k -> k/2 or (k+1)/2 until result is prime", starting with prime(n)+1.

3, 2, 3, 2, 3, 7, 5, 5, 3, 2, 2, 19, 11, 11, 3, 7, 2, 31, 17, 5, 37, 5, 11, 23, 13, 13, 13, 7, 7, 29, 2, 17, 5, 5, 19, 19, 79, 41, 11, 11, 23, 23, 3, 97, 13, 13, 53, 7, 29, 29, 59, 2, 61, 2, 17, 17, 17, 17, 139, 71, 71, 37, 5, 5, 157, 5, 83, 43, 11, 11, 89, 23, 23, 47, 3, 3, 13

Offset: 1

Author

Wouter Meeussen

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A039634-A039645.

Cf. A010051, A000040, A039645, A039639, A039635.

Programs

Haskell

a039641 = until ((== 1) . a010051) (flip div 2 . (+ 1)) . (+ 1) . a000040
-- Reinhard Zumkeller, Nov 17 2013

Mathematica

(* See A039635. *)
Table[NestWhile[If[EvenQ[#],#/2,(#+1)/2]&,n+1,!PrimeQ[#]&],{n,Prime[ Range[ 80]]}] (* Harvey P. Dale, May 12 2014 *)

Extensions

Offset corrected by Reinhard Zumkeller, Nov 17 2013