A273601 - OEIS

A273601

Numbers k such that (11^k - 9^k)/2 is prime.

5, 31, 271, 929, 2789, 4153

OFFSET

1,1

COMMENTS

All terms are prime.

The corresponding primes: 51001, 95780952266636767336259095696501, ...

a(7) > 50000. - Michael S. Branicky, Nov 11 2024

LINKS

MATHEMATICA

Select[Range[1, 10000], PrimeQ[(11^# - 9^#)/2] &]

PROG

(PARI) for(n=1, 10000, if(isprime((11^n - 9^n)/2), print1(n, ", ")))

CROSSREFS

KEYWORD

nonn,more,hard

AUTHOR

STATUS

approved