A096254 Numbers n such that 5*10^n + 3 is prime.

1, 2, 3, 8, 18, 20, 31, 42, 103, 175, 181, 531, 706, 1077, 1177, 1552, 19737, 32197, 51508, 58275, 62233, 90033

Offset

1,2

Comments

a(23) > 2*10^5. - Robert Price, Aug 03 2015

Links

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

Makoto Kamada, Prime numbers of the form 500...003.

Sabin Tabirca and Kieran Reynolds, Lacunary Prime Numbers.

Formula

a(n) = A101568(n) + 1.

Example

1, 2 and 3 are in the list because 53, 503 and 5003 are all prime.
500000003 (5*10^8 + 3) is the next similar prime, so 8 is the next term in the sequence.

Mathematica

Do[ If[ PrimeQ[5*10^n + 3], Print[n]], {n, 10000}] (* Robert G. Wilson v, Aug 13 2004 *)

Prog

(PARI) is(n)=isprime(5*10^n+3) \\ Charles R Greathouse IV, Sep 27 2016

Crossrefs

Cf. A101568.

Sequence in context: A101182 A009207 A290878 * A091765 A368882 A036746

Adjacent sequences: A096251 A096252 A096253 * A096255 A096256 A096257

Keyword

more,nonn

Author

Carl R. White, Aug 10 2004

Extensions

a(12)-a(16) from Robert G. Wilson v, Aug 13 2004

a(17)-a(22) from Kamada data by Robert Price, Dec 09 2010

Status

approved