A268448 Numbers k such that (35*10^k - 11)/3 is prime.

1, 2, 4, 5, 6, 7, 14, 21, 27, 34, 53, 72, 96, 145, 168, 191, 192, 309, 393, 502, 667, 1055, 1534, 1710, 4171, 4838, 4950, 9932, 10860, 11906, 14148, 17184, 27054, 31435

Offset: 1

Author

Robert Price, Feb 04 2016

Keywords

• more
• nonn

Comments

Numbers k such that digits 11 followed by k-1 occurrences of digit 6 followed by digit 3 is prime. E.g., 116666...666663.

a(35) > 3*10^5. - Robert Price, Oct 16 2015

Examples

			7 is in this sequence because (35*10^7 - 11)/3 = 116666663 is prime.
		

Links

• Makoto Kamada, Search for 116w3.

Crossrefs

Cf. A056654.

Programs

Magma

[n: n in [0..400] |IsPrime((35*10^n-11) div 3)]; // Vincenzo Librandi, Feb 05 2016

Mathematica

Select[Range[0, 100000], PrimeQ[(35*10^# - 11)/3] &]

PARI

lista(nn) = {for(n=1, nn, if(ispseudoprime((35*10^n-11)/3), print1(n, ", ")));} \\ Altug Alkan, Feb 05 2016