A107280 Numbers k such that 22446688 * 10^k + 1 is prime.

11, 36, 53, 54, 109, 123, 259, 380, 877, 1205, 1795, 14153, 21965

Offset

1,1

Comments

These are almost-all-even-digits primes and they have all been certified. No more terms up to 25000. Primality proof for the largest: PFGW Version 20041001.Win_Stable (v1.2 RC1b) [FFT v23.8] Primality testing 22446688*10^21965+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 3 22446688*10^21965+1 is prime! (70.7023s+0.0215s)

Links

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

R. Ondrejka, The Top Ten: a Catalogue of Primal Configurations.

Prog

(PARI) is(n)=ispseudoprime(22446688*10^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A068690.

Sequence in context: A243151 A225130 A191292 * A044088 A044469 A015246

Adjacent sequences: A107277 A107278 A107279 * A107281 A107282 A107283

Keyword

nonn

Author

Jason Earls, May 19 2005

Status

approved