A108327 -id:A108327 - cp's OEIS frontend

A108506 Integers n such that 10^n-59 is prime.

2, 3, 4, 8, 20, 38, 95, 248, 263, 303, 304, 410, 438, 548, 688, 1074, 1575, 8364, 9910, 15910, 37344

Offset: 1

Julien Peter Benney (jpbenney(AT)ftml.net), Jul 06 2005

Certified primality of numbers corresponding to terms 410, 438, 548, 688, 1074 and 1575 with Primo. - Ryan Propper, Jul 08 2005
No other terms <40000.
See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99941".

			8 is a member because: n = 8 gives 10^8-59 = 100000000-59 = 99999941, which is prime.

Makoto Kamada, List of near-repdigit-related prime numbers.
Index entries for primes involving repunits.

Cf. A089675, A095714, A092767, A108327, A108328, A108329, A108330, A108331, A108332, A177418.

a(18)-a(20) from Kamada data by Robert Price, Dec 10 2010
a(21) by Robert Price, Dec 16 2010
Edited by Ray Chandler, Dec 23 2010

A278470 Numbers k such that 10^k - 201 is prime.

Original entry on oeis.org

13, 20, 40, 43, 73, 85, 576, 1676, 33565

Offset: 1

Vincenzo Librandi, Nov 23 2016

For k > 2, numbers k such that k-3 occurrences of the digit 9 followed by the digits 799 is prime.

a(9) > 10000. - Robert G. Wilson v, Nov 24 2016

			13 is in this sequence because 10^13 - 201 = 9999999999799 is prime.
Initial terms and associated primes:
a(1) = 13, 9999999999799;
a(2) = 20, 99999999999999999799;
a(3) = 40, 9999999999999999999999999999999999999799; etc.

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

Cf. A108327 (10^n-21), this sequence (10^n-201), A278397 (10^n-20001), A278471 (10^n-2001).

[n: n in [3..500] | IsPrime(10^n-201)];

A278470:=n->`if`(isprime(10^n-201), n, NULL): seq(A278470(n), n=1..10^3); # Wesley Ivan Hurt, Dec 08 2016

Select[Range[3, 2000], PrimeQ[10^# - 201] &]

is(n)=ispseudoprime(10^n-201) \\ Charles R Greathouse IV, Jun 06 2017

a(9) from Kamada data by Tyler Busby, May 03 2024

A108493 Integers n such that 10^n-57 is prime.

Original entry on oeis.org

2, 7, 10, 11, 17, 19, 39, 49, 50, 61, 95, 106, 187, 196, 849, 889, 6436, 7370, 14446, 19647, 34399, 39922, 81297, 84305

Offset: 1

Julien Peter Benney (jpbenney(AT)ftml.net), Jul 06 2005

Numbers corresponding to terms 849 and 889 are certified primes. (Primo 2.2.0 beta) - Ryan Propper, Jul 13 2005
No additional terms <100000.
See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99943".

			n = 7 is a member because: 10^7-57 = 10000000-57 = 9999943, which is prime.

Makoto Kamada, List of near-repdigit-related prime numbers.
Index entries for primes involving repunits.

Cf. A089675, A095714, A092767, A108327, A108328, A108329, A108330, A108331, A108332, A177417.

a(17)-a(19) from Kamada data by Robert Price, Dec 10 2010
a(20) from Kamada data by Robert Price, Dec 14 2010
a(21)-a(22) from Robert Price, Dec 15 2010
Edited by Ray Chandler, Dec 23 2010
a(23-24)=81297,84305 from Robert Price, May 29 2011

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A108506 Integers n such that 10^n-59 is prime.

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A278470 Numbers k such that 10^k - 201 is prime.

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A108493 Integers n such that 10^n-57 is prime.

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