A178642 Primes p such that primorial(p)/2 - 2 is not prime.

3, 29, 37, 43, 47, 59, 61, 67, 73, 79, 83, 89, 97, 101, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 31 2010

Keywords

• nonn

Examples

			3*5*7*11*13*17*19*23*29 - 2 = 43*167*450473 is composite.
		

Crossrefs

Cf. A002110, A096177, A096547, A178641.

Programs

Mathematica

pp=1;lst={};Do[p=Prime[n];pp*=p;If[ !PrimeQ[pp-2],AppendTo[lst,p]],{n,2,2*5!}];lst
Transpose[Select[With[{pros=Rest[FoldList[Times,1,Prime[Range[100]]]]}, Table[ {Prime[n], pros[[n]]},{n,100}]],!PrimeQ[Last[#]/2-2]&]][[1]] (* Harvey P. Dale, Mar 02 2012 *)