A235053 Numbers k of the form p^2 + 1 (for prime p) where k^2 + 1 is also prime.
10, 26, 170, 1850, 2210, 16130, 69170, 76730, 85850, 113570, 120410, 157610, 196250, 218090, 237170, 253010, 332930, 351650, 368450, 452930, 528530, 537290, 597530, 734450, 786770, 822650, 1329410, 2036330, 2211170
Offset: 1
Keywords
Examples
351650 = 593^2 + 1 (593 is prime) and 351650^2 + 1 is prime, so 351650 is a member of this sequence.
Links
- Seiichi Manyama, Table of n, a(n) for n = 1..1000
Programs
-
Python
import sympy from sympy import isprime {print(n**2+1) for n in range(10**7) if isprime(n) if isprime((n**2+1)**2+1)}
Comments