A178430 Numbers n such that 10^n - 53 is prime.

2, 3, 11, 15, 23, 29, 44, 71, 83, 95, 159, 383, 404, 548, 633, 6409, 8793, 24146, 25727, 64436, 74335, 76875

Offset

1,1

Comments

The next term, if it exists, is > 100000.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99947".

Links

Table of n, a(n) for n=1..22.

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

Index entries for primes involving repunits.

Example

10^3 - 53 = 947 which is a prime number.

Mathematica

m=1000; For[n=1, n<m, If[PrimeQ[10^n-53], Print[n]]; n++ ]

Prog

(PARI) is(n)=ispseudoprime(10^n-53) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A108330, A108328.

Sequence in context: A042235 A050587 A293026 * A295128 A360520 A066687

Adjacent sequences: A178427 A178428 A178429 * A178431 A178432 A178433

Keyword

more,nonn

Author

Robert Price, Dec 21 2010

Extensions

Corrected terms a(17) and a(18) by Robert Price, Dec 24 2010

a(20-22)=64436,74335,76875 from Robert Price, May 29 2011

Status

approved