A178429 Numbers n such that 10^n - 51 is prime.
4, 48, 64, 313, 484, 642, 11950, 15845, 18580, 50929
Offset: 1
Examples
10^4 - 51 = 9949 which is a prime number.
Links
- Makoto Kamada, Near-repdigit numbers of the form AA...AABA.
- Makoto Kamada, Prime numbers of the form 99...9949.
- Index entries for primes involving repunits.
Programs
-
Maple
A178429:=n->`if`(isprime(10^n-51), n, NULL): seq(A178429(n), n=1..1000); # Wesley Ivan Hurt, Nov 26 2014
-
Mathematica
m = 1000; For[n = 1, n < m, If[PrimeQ[10^n - 51], Print[n]]; n++ ]
-
PARI
is(n)=ispseudoprime(10^n-51) \\ Charles R Greathouse IV, Jun 06 2017
Extensions
a(10) = 50929 found by Robert Price and added by Patrick De Geest, Nov 26 2014