A248352 Numbers k such that 10^k - 987654321 is prime.

986, 1240, 1928, 4054, 14252, 47528, 101728

Offset: 1

Author

Derek Orr, Oct 05 2014

Keywords

• nonn
• hard
• more

Comments

Note that 987654321 is the largest pandigital number in base-10, omitting 0.

Crossrefs

Cf. A248349, A248350, A248351, A050289.

Programs

Mathematica

Select[Range[10000], PrimeQ[10^# - 987654321] &] (* Robert Price, Dec 05 2019 *)

PARI

for(n=1,10^4,if(ispseudoprime(10^n-987654321),print1(n,", ")))

Extensions

a(6)-a(7) from Robert Price, Dec 05 2019