A198273 Primes not of the form p*q + p + q for any primes p and q.

2, 3, 5, 7, 13, 19, 29, 37, 43, 61, 67, 73, 97, 101, 103, 109, 137, 139, 149, 157, 163, 173, 181, 193, 197, 199, 211, 223, 229, 233, 241, 257, 277, 281, 283, 307, 313, 317, 331, 337, 347, 349, 353, 367, 373, 379, 389, 397, 401, 409, 421, 433, 457, 461, 463

Offset

1,1

Comments

A067432(A049084(a(n))) = 0; complement of A066938 with respect to A000040.

Links

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

Mathematica

nn = 500; n2 = PrimePi[nn/3]; Complement[Prime[Range[PrimePi[nn]]], Select[Union[Flatten[Table[(Prime[i] + 1) (Prime[j] + 1) - 1, {i, n2}, {j, n2}]]], # <= nn && PrimeQ[#] &]] (* T. D. Noe, Nov 22 2011 *)
Reap[For[P=2, P<500, P = NextPrime[P], If[Reduce[P == p*q + p + q, {p, q}, Primes] === False, Print[P]; Sow[P]]]][[2, 1]] (* Jean-François Alcover, Dec 10 2015 *)

Prog

(Haskell)
a198273 n = a198273_list !! (n-1)
a198273_list = map a000040 $ filter ((== 0) . a067432) [1..]
(PARI) do(lim)=my(v=Set(), t);; forprime(p=3, lim, forprime(q=2, p-1, t=p*q+p+q; if(t>lim, break); v=setunion(v, [t]))); setminus(primes(primepi(lim)), v) \\ Charles R Greathouse IV, Nov 22 2011

Crossrefs

Cf. A000040, A049084, A066938, A067432.

Sequence in context: A169647 A072467 A062326 * A066076 A136288 A344604

Adjacent sequences: A198270 A198271 A198272 * A198274 A198275 A198276

Keyword

nonn,nice

Author

Reinhard Zumkeller, Oct 23 2011

Status

approved