A178429 Numbers n such that 10^n - 51 is prime.

4, 48, 64, 313, 484, 642, 11950, 15845, 18580, 50929

Offset

1,1

Links

Table of n, a(n) for n=1..10.

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.

Example

10^4 - 51 = 9949 which is a prime number.

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++ ]

Prog

(PARI) is(n)=ispseudoprime(10^n-51) \\ Charles R Greathouse IV, Jun 06 2017

Crossrefs

Cf. A108330, A108328.

Sequence in context: A358885 A358889 A225987 * A370417 A242225 A157818

Adjacent sequences: A178426 A178427 A178428 * A178430 A178431 A178432

Keyword

more,nonn

Author

Robert Price, Dec 21 2010

Extensions

a(10) = 50929 found by Robert Price and added by Patrick De Geest, Nov 26 2014

Status

approved