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A277066 Numbers k such that (266*10^k - 11) / 3 is prime. 0
1, 2, 3, 4, 7, 9, 10, 14, 28, 58, 93, 121, 135, 207, 350, 423, 602, 859, 1026, 1864, 1966, 13738, 23299, 28126, 38691, 39403, 47499, 93577, 124022, 177577 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
For k>0, numbers such that the digits 88 followed by k-1 occurrences of the digit 6 followed by the digit 3 is prime (see Example section).
a(31) > 3*10^5.
LINKS
Makoto Kamada, Search for 886w3.
EXAMPLE
3 is in this sequence because (266*10^3 - 11) / 3 = 88663 is prime.
Initial terms and primes associated:
a(1) = 1, 883;
a(2) = 2, 8863;
a(3) = 3, 88663;
a(4) = 4, 886663;
a(5) = 7, 886666663, etc.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(266*10^# - 11) / 3] &]
PROG
(PARI) is(n)=ispseudoprime((266*10^n - 11)/3) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A057912 A141748 A057267 * A138576 A259483 A187503
KEYWORD
nonn,more
AUTHOR
Robert Price, Sep 27 2016
EXTENSIONS
a(29)-a(30) from Robert Price, Apr 01 2020
STATUS
approved

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Last modified April 24 22:17 EDT 2024. Contains 371964 sequences. (Running on oeis4.)