A110983 Integers k such that 5*10^k + 51 is prime.

1, 3, 4, 16, 430, 727, 1415, 2691, 3160, 3904, 5464, 19875, 65255, 68524

Offset

1,2

Comments

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "50051".

a(15) > 10^5. - Robert Price, Jan 28 2017

Links

Table of n, a(n) for n=1..14.

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

Index entries for primes involving repunits.

Example

k = 4 is a member because: 5*10^4+51 = 5*10000+51 = 50000+51 = 50051, which is prime.

Mathematica

Select[Range[1, 1000], PrimeQ[5*10^# + 51] &] (* Julien Kluge, Dec 15 2016 *)

Crossrefs

Cf. A049054, A088274, A088275, A095688, A107083, A108049, A108050, A108052, A108054.

Sequence in context: A353155 A252606 A248240 * A360795 A370581 A100560

Adjacent sequences: A110980 A110981 A110982 * A110984 A110985 A110986

Keyword

more,nonn

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Oct 04 2005

Extensions

a(11)-a(12) from Ray Chandler, Dec 23 2010

Prepended a(1)=1 by Robert Price, Jan 28 2017

a(13)-a(14) from Robert Price, Jan 28 2017

Status

approved