OFFSET
1,2
COMMENTS
a(6) > 6000. - Tyler NeSmith, Dec 05 2021
EXAMPLE
43 is prime ==> a(1) = 0.
3661 = 7 * 523.
360601 = 19 * 18979.
36006001 = 67 * 537403.
3600060001 = 457 * 7877593.
360000600001 = 7 * 51428657143.
36000006000001 = 379 * 94986823219.
3600000060000001 = 7 * 43 * 64609 * 185115589.
360000000600000001 = 19 * 18947368452631579.
36000000006000000001 = 307 * 1249 * 1071121 * 87652267.
3600000000060000000001 is prime ==> a(2) = 10.
PROG
(PARI) for(k=0, 1e3, if(ispseudoprime(36*100^k+6*10^k+1), print1(k", ")))
CROSSREFS
KEYWORD
nonn,more,base
AUTHOR
Seiichi Manyama, Aug 15 2019
EXTENSIONS
a(6) from Michael S. Branicky, Apr 24 2023
a(7) from Michael S. Branicky, Sep 07 2024
STATUS
approved