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A107280 Numbers n such that 22446688 * 10^n + 1 is prime. 0
11, 36, 53, 54, 109, 123, 259, 380, 877, 1205, 1795, 14153, 21965 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 22 11:46 EDT 2019. Contains 322330 sequences. (Running on oeis4.)