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A276492 Numbers k such that 5*10^k + 59 is prime. 0
1, 3, 7, 9, 10, 19, 21, 22, 43, 46, 58, 87, 216, 549, 604, 1147, 1858, 2952, 3684, 4057, 4246, 4354, 8212, 8289, 9013, 16968, 19107, 57754, 61348, 88254 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For k>1, numbers such that the digit 5 followed by k-2 occurrences of the digit 0 followed by the digits 59 is prime (see Example section).

a(31) > 2*10^5.

LINKS

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

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

Makoto Kamada, Search for 50w59.

EXAMPLE

3 is in this sequence because 5*10^3 + 59 = 5059 is prime.

Initial terms and primes associated:

a(1) = 1, 109;

a(2) = 3, 5059;

a(3) = 7, 50000059;

a(4) = 9, 5000000059;

a(5) = 10, 50000000059, etc.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[5*10^# + 59] &]

PROG

(PARI) is(n)=ispseudoprime(5*10^n + 59) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

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

Sequence in context: A083214 A091210 A333911 * A023992 A179197 A097270

Adjacent sequences:  A276489 A276490 A276491 * A276493 A276494 A276495

KEYWORD

nonn,more

AUTHOR

Robert Price, Sep 05 2016

STATUS

approved

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Last modified July 12 05:35 EDT 2020. Contains 335658 sequences. (Running on oeis4.)