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A198273 Primes not of the form p*q + p + q for any primes p and q. 3
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 (list; graph; refs; listen; history; text; internal format)
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-Fran├žois 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

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Last modified October 6 10:31 EDT 2022. Contains 357263 sequences. (Running on oeis4.)