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A273944 Numbers n such that (266*10^n-17)/3 is prime. 0
0, 1, 2, 3, 7, 8, 11, 14, 24, 29, 50, 78, 99, 192, 226, 519, 613, 651, 1492, 3720, 6567, 6791, 7226, 8471, 9050, 13521, 14255, 33529, 44072, 47844, 64102 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

For n>1, numbers n such that the digits 88 followed by n-1 occurrences of the digit 6 followed by the digit 1 is prime (see Example section).

a(32) > 10^5.

LINKS

Table of n, a(n) for n=1..31.

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

Makoto Kamada, Search for 886w1.

EXAMPLE

3 is in this sequence because (266*10^3-17)/3 = 88661 is prime.

Initial terms and primes associated:

a(1) = 0, 83;

a(2) = 1, 881;

a(3) = 2, 8861;

a(4) = 3, 88661;

a(5) = 7, 886666661, etc.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[(266*10^#-17)/3] &]

PROG

(PARI) isok(n) = isprime((266*10^n-17)/3); \\ Michel Marcus, Jun 18 2016

CROSSREFS

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

Sequence in context: A002274 A329783 A287675 * A214324 A102664 A055053

Adjacent sequences:  A273941 A273942 A273943 * A273945 A273946 A273947

KEYWORD

nonn,more

AUTHOR

Robert Price, Jun 17 2016

STATUS

approved

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Last modified February 22 15:05 EST 2020. Contains 332137 sequences. (Running on oeis4.)