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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.
4
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
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 *)
KEYWORD
nonn
AUTHOR
STATUS
approved