A167838 - OEIS

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A167838

Four-times-isolated primes: primes p such that neither p+-2, p+-4, p+-6 nor p+-8 is prime.

2, 211, 293, 631, 787, 797, 839, 1249, 1259, 1399, 1409, 1471, 1511, 1637, 1709, 1801, 1811, 1847, 1889, 2039, 2053, 2099, 2179, 2503, 2521, 2579, 2633, 2647, 2767, 2777, 2819, 2927, 2939, 3109, 3137, 3271, 3433, 3571, 3593, 3659, 3779, 3833, 3863, 3967

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OFFSET

1,1

COMMENTS

2 together with (A137871: prime numbers isolated from neighboring primes by more than 8).

LINKS

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

EXAMPLE

a(1)=2 (-6,-4,-2,0,4,6,8,10 are nonprimes); a(2)=211 (203,205,207,209,213,215,217,219 are nonprimes).

MAPLE

Primes:= select(isprime, {2, seq(i, i=3..10000, 2)}):

S:=Primes minus `union`(seq(map(`+`, Primes, i), i=[-2, 2, -4, 4, -6, 6, -8, 8])):