A287351 Numbers k such that (10^k*361 - 163)/9 is prime (k > 0).

1, 3, 9, 15, 27, 37, 165, 207, 897, 5761, 16753, 17995, 96567

Offset

1,2

Comments

a(14) > 10^5. - Robert Price, Oct 31 2017

Links

Table of n, a(n) for n=1..13.

Example

If k = 1 then (10^1*361 - 163)/9 = 383 (prime), so 1 is a term.
If k = 9 then (10^9*361 - 163)/9 = 40111111093 (prime), so 9 is a term.

Mathematica

ParallelMap[ If[ PrimeQ[ (10^# 361-163)/9], #, Nothing] &, Range[6000]]

Crossrefs

Cf. A247643.

Sequence in context: A087031 A089632 A247643 * A256388 A082897 A363523

Adjacent sequences: A287348 A287349 A287350 * A287352 A287353 A287354

Keyword

nonn,hard,more

Author

Mikk Heidemaa, May 23 2017

Extensions

a(13) from Robert Price, Oct 31 2017

Status

approved