A102249 Numbers k such that k1111 is prime.

10, 13, 31, 36, 51, 57, 61, 69, 72, 78, 79, 90, 91, 97, 117, 120, 127, 129, 135, 138, 153, 156, 166, 174, 183, 184, 189, 201, 205, 210, 222, 225, 226, 234, 237, 240, 241, 244, 252, 261, 265, 273, 276, 280, 285, 292, 304, 306, 309, 318, 322, 325, 327, 337, 345

Offset: 1

Author

Parthasarathy Nambi, Feb 18 2005

Keywords

• nonn
• base

Examples

			At k=10, k1111 = 101111 (prime).
At k=90, k1111 = 901111 (prime).
At k=138, k1111 = 1381111 (prime).
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A024912.

Programs

Mathematica

Select[ Range[ 350], PrimeQ[ FromDigits[ Flatten[ IntegerDigits /@ { #, 1, 1, 1, 1}]]] &] (* Robert G. Wilson v, Feb 21 2005 *)
Select[Range[400],PrimeQ[#*10^4+1111]&] (* Harvey P. Dale, Jul 14 2019 *)

Extensions

More terms from Robert G. Wilson v, Feb 21 2005