A158719 Primes p such that p1 = floor(p/2)+p is not prime and p2 = ceiling(p/2)+p is not prime, p3 = floor(p1/2)+p1 is not prime and p5 = ceiling(p1/2)+p1 is not prime, p4 = floor(p2/2)+p2 is not prime and p6 = ceiling(p2/2)+p2 is not prime.

83, 97, 113, 227, 229, 251, 269, 271, 277, 283, 313, 317, 331, 353, 389, 397, 419, 433, 457, 463, 491, 503, 509, 523, 557, 563, 593, 599, 601, 617, 641, 653, 683, 691, 733, 743, 751, 757, 761, 773, 797, 823, 829, 857, 863, 937, 941, 971, 977, 1013, 1031, 1049

Offset

1,1

Links

Table of n, a(n) for n=1..52.

Mathematica

lst={}; Do[p=Prime[n]; If[ !PrimeQ[p1=Floor[p/2]+p]&&!PrimeQ[p2=Ceiling[p/2]+p], If[ !PrimeQ[p3=Floor[p1/2]+p1]&&!PrimeQ[p5=Ceiling[p1/2]+p1], If[ !PrimeQ[p4=Floor[p2/2]+p2]&&!PrimeQ[p6=Ceiling[p2/2]+p2], AppendTo[lst, Prime[n]]]]], {n, 6!}]; lst
nonpQ[p_]:=Module[{p1=Floor[p/2]+p, p2=Ceiling[p/2]+p}, NoneTrue[ {p1, p2, Floor[ p1/2]+p1, Ceiling[p1/2]+p1, Floor[p2/2]+p2, Ceiling[p2/2]+ p2}, PrimeQ]]; Select[Prime[Range[200]], nonpQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 21 2019 *)

Crossrefs

Cf. A158708, A158709, A158710, A158711, A158712, A158713, A158714.

Sequence in context: A090156 A220121 A335916 * A160028 A115258 A316970

Adjacent sequences: A158716 A158717 A158718 * A158720 A158721 A158722

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 24 2009

Status

approved