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A277066

Numbers k such that (266*10^k - 11) / 3 is prime.

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

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OFFSET

1,2

COMMENTS

For k > 0, numbers k 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

Table of n, a(n) for n=1..30.

Makoto Kamada, Factorization of near-repdigit-related numbers.

Makoto Kamada, Search for 886w3.

EXAMPLE

3 is in this sequence because (266*10^3 - 11) / 3 = 88663 is prime.

Initial terms and associated primes:

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

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Sequence in context: A057912 A141748 A057267 * A138576 A259483 A187503

Adjacent sequences: A277063 A277064 A277065 * A277067 A277068 A277069

KEYWORD

nonn,more

AUTHOR

Robert Price, Sep 27 2016

EXTENSIONS

a(29)-a(30) from Robert Price, Apr 01 2020

STATUS

approved

URL: https://oeis.org/A277066

⇱ A277066 - OEIS