A178531 Numbers n such that 10^n - 93 is prime.

2, 3, 4, 5, 6, 7, 11, 57, 61, 70, 127, 223, 237, 240, 310, 467, 651, 1935, 2333, 3457, 4456, 6048, 11289, 12150, 24693, 28437, 31123, 32909, 52041, 58225, 68297, 201801

Offset

1,1

Comments

a(33) > 3*10^5.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99907" or "9w07".

Links

Table of n, a(n) for n=1..32.

Makoto Kamada, List of near-repdigit-related prime numbers.

Index entries for primes involving repunits.

Example

10^3 - 93 = 907 which is a prime number.

Mathematica

m=1000; For[n=1, n<m, If[PrimeQ[10^n-93], Print[n]]; n++ ]

Prog

(PARI) is(n)=ispseudoprime(10^n-93) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A108330, A108328.

Sequence in context: A059768 A271835 A118599 * A358254 A175500 A356253

Adjacent sequences: A178528 A178529 A178530 * A178532 A178533 A178534

Keyword

more,nonn

Author

Robert Price, Dec 23 2010

Extensions

a(29-31) from Robert Price, May 29 2011

a(32) from Robert Price, Jun 21 2023

Status

approved