A275783 Numbers n such that 10^n + 9^(n+1) is prime.

2, 3, 6, 11, 44, 64, 83, 123, 166, 381, 446, 1221, 1540, 3156, 5117, 5476, 6291, 6353, 13053, 15158, 23904, 78288, 82254, 91230

Offset: 1

Author

Robert Price, Aug 08 2016

Keywords

• nonn
• more

Comments

a(25) > 10^5.

Examples

			3 is a member since 10^3 + 9^4 = 1000 + 6561 = 7561 which is a prime number.
		

Crossrefs

Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884.

Programs

Mathematica

Select[Range[0, 100000], PrimeQ[10^# + 9^(# + 1)] &]

PARI

is(n)=ispseudoprime(10^n+9^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017