A091310 Primes not of the form p*q + p - q with prime p and q.

2, 3, 11, 23, 47, 53, 59, 71, 79, 83, 101, 107, 131, 163, 167, 173, 179, 191, 223, 227, 239, 251, 263, 269, 293, 311, 331, 347, 359, 367, 383, 419, 431, 439, 443, 467, 479, 491, 503, 509, 547, 563, 587, 599, 607, 641, 647, 653, 659, 683, 691, 719, 727, 733

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 1000: # for terms <= N
P:= select(isprime, [2, seq(i, i=3..N, 2)]):
nP:= nops(P):
S:= {}:
for i from 1 to nP do
  for j from 1 to nP do
    x:= P[i]*P[j]+P[i]-P[j];
    if x > N then break fi;
    if isprime(x) then S:= S union {x} fi
od od:
sort(convert(convert(P, set) minus S, list)); # Robert Israel, Jun 05 2025

Mathematica

x = Take[ Select[ Union[ Flatten[ Table[ Prime[p]*Prime[q] + Prime[p] - Prime[q], {p, 116}, {q, 116}]]], PrimeQ[ # ] &], 200]; y = Table[ Prime[i], {i, PrimePi[ p[[ -1]] ]}]; Take[ Complement[y, x], 54] (* Robert G. Wilson v *)

Crossrefs

Primes not in A091301.

Sequence in context: A082739 A158017 A346605 * A040994 A141123 A263729

Adjacent sequences: A091307 A091308 A091309 * A091311 A091312 A091313

Keyword

nonn

Author

Zak Seidov, Feb 21 2004

Status

approved