login
A248351
Numbers k such that 10^k + 987654321 is prime.
4
6, 11, 15, 27, 42, 113, 135, 186, 207, 503, 2999, 3005, 3487, 5718, 7265, 7629, 11987, 16063, 27379, 64770, 73579, 96504, 116557
OFFSET
1,1
COMMENTS
Note that 987654321 is the largest pandigital number in base-10, omitting 0.
MATHEMATICA
Select[Range[1000], PrimeQ[10^# + 987654321] &] (* Vincenzo Librandi, Oct 12 2014 *)
PROG
(PARI) for(n=1, 10^4, if(ispseudoprime(10^n+987654321), print1(n, ", ")))
(Magma) [n: n in [1..500] | IsPrime(10^n+987654321)]; // Vincenzo Librandi, Oct 12 2014
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Derek Orr, Oct 05 2014
EXTENSIONS
a(9) corrected and a(19)-a(23) added by Robert Price, Dec 05 2019
STATUS
approved