A138646 Primes p such that 5*p-2 is composite.

2, 7, 13, 19, 29, 31, 37, 41, 43, 61, 67, 73, 79, 83, 97, 103, 107, 109, 127, 139, 151, 157, 163, 167, 179, 181, 193, 199, 211, 223, 227, 229, 241, 251, 263, 269, 271, 277, 281, 283, 293, 307, 313, 331, 337, 349, 353, 359, 367, 373, 379, 389, 397, 409, 419

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

5*2-2=8, 5*7-2=33, 5*13-2=63,...

Mathematica

a={}; Do[p=Prime[n]; If[ !PrimeQ[5*p-2], AppendTo[a, p]], {n, 8^2}]; a
Select[Prime[Range[100]], !PrimeQ[5#-2]&] (* Harvey P. Dale, Dec 16 2012 *)

Crossrefs

Sequence in context: A109346 A140550 A271114 * A118755 A231383 A156012

Adjacent sequences: A138643 A138644 A138645 * A138647 A138648 A138649

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 15 2008

Extensions

More terms from Vincenzo Librandi, Apr 01 2010

Status

approved