

A274238


Numbers n such that (26*10^n  119)/3 is prime.


0



1, 2, 3, 4, 6, 22, 25, 29, 59, 89, 221, 453, 535, 1708, 2242, 2413, 3581, 4234, 4848, 5380, 6548, 8654, 11035, 17308, 27634, 28807, 35481, 79678, 80875
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

For n>1, numbers n such that the digit 8 followed by n2 occurrences of the digit 6 followed by the digits 27 is prime (see Example section).
a(30) > 10^5.


LINKS

Table of n, a(n) for n=1..29.
Makoto Kamada, Factorization of nearrepdigitrelated numbers.
Makoto Kamada, Search for 86w27.


EXAMPLE

3 is in this sequence because (26*10^3  119)/3 = 8627 is prime.
Initial terms and primes associated:
a(1) = 1, 47;
a(2) = 2, 827;
a(3) = 3, 8627;
a(4) = 4, 86627;
a(5) = 6, 8666627, etc.


MATHEMATICA

Select[Range[0, 100000], PrimeQ[(26*10^#  119)/3] &]


PROG

(Magma) [n: n in [1..500] IsPrime((26*10^n119) div 3)]; // Vincenzo Librandi, Jul 07 2016
(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime((26*10^n119)/3), print1(n, ", "))); \\ Altug Alkan, Jul 08 2016


CROSSREFS

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
Sequence in context: A220702 A342503 A217351 * A115035 A219048 A329577
Adjacent sequences: A274235 A274236 A274237 * A274239 A274240 A274241


KEYWORD

nonn,more


AUTHOR

Robert Price, Jul 06 2016


STATUS

approved



