A268448 - OEIS

A268448

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

505

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

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

LINKS

Table of n, a(n) for n=1..34.

Makoto Kamada, Search for 116w3.

EXAMPLE

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

MATHEMATICA

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

PROG

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

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

CROSSREFS

Cf. A056654.

Sequence in context: A092058 A134532 A282278 * A230581 A361825 A248962

Adjacent sequences: A268445 A268446 A268447 * A268449 A268450 A268451

KEYWORD

more,nonn

AUTHOR

Robert Price, Feb 04 2016

STATUS

approved