OFFSET
1,2
COMMENTS
Looking at the format 90k+77 modulo 9 and modulo 10 we see that all entries of A142329 have digital root 5 and last digit 7. (Reverting the process is an application of the Chinese remainder theorem.)
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = (A142329(n) - 77)/90.
MATHEMATICA
Select[Range[0, 400], PrimeQ[90 #+77]&] (* Vincenzo Librandi, Dec 11 2011 *)
PROG
(Magma) [n: n in [0..200] | IsPrime(90*n+77)]; // Vincenzo Librandi, Dec 11 2011
(PARI) is(n)=isprime(90*n+77) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
J. W. Helkenberg, Dec 05 2011
STATUS
approved