Number of primes p < 10^n such that both 2*p+1 and 4*p+1 are composite.
A210684
Number of primes p < 10^n such that both 2*p+1 and 4*p+1 are composite.
Terms
- a(0) =0a(1) =7a(2) =101a(3) =864a(4) =7365a(5) =63331a(6) =554839a(7) =4931118a(8) =44339730a(9) =402709395a(10) =3687732409a(11) =34007530868
External references
- oeis: A210684