

A102249


Numbers k such that k1111 is prime.


2



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
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OFFSET

1,1


LINKS

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


EXAMPLE

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


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 *)


CROSSREFS

Cf. A024912.
Sequence in context: A126973 A220045 A101215 * A195313 A219829 A062370
Adjacent sequences: A102246 A102247 A102248 * A102250 A102251 A102252


KEYWORD

nonn,base


AUTHOR

Parthasarathy Nambi, Feb 18 2005


EXTENSIONS

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


STATUS

approved



