login
A102933
Numbers k such that 10^k + 3*R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
1
1, 2, 4, 7, 10, 13, 14, 22, 23, 29, 38, 50, 53, 67, 104, 350, 376, 412, 1205, 1835, 2510, 2668, 6097, 8296, 14296, 43369, 127349, 142034
OFFSET
1,2
COMMENTS
Also numbers k such that (4*10^k + 17)/3 is prime.
a(29) > 2*10^5. - Tyler Busby, Feb 01 2023
FORMULA
a(n) = A102014(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(4*10^n + 17)/3], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A007303 A102988 A080137 * A122019 A190279 A186325
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Dec 16 2004
EXTENSIONS
Addition of a(25) from Kamada data by Robert Price, Dec 08 2010
a(26) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013
a(27)-a(28) from Tyler Busby, Feb 01 2023
STATUS
approved