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A301635
Numbers k such that 5^k + 5*k + 1 is prime.
3
0, 1, 11, 25, 35, 85, 499, 1403, 3511, 3739, 8005
OFFSET
1,3
COMMENTS
a(12), if it exists, is greater than 20000. - Vaclav Kotesovec, Mar 25 2018
a(12), if it exists, is greater than 80000. - Michael S. Branicky, Sep 03 2024
MATHEMATICA
Flatten[{0, Select[Range[1000], PrimeQ[5^# + 5*# + 1] &]}] (* Vaclav Kotesovec, Mar 25 2018 *)
PROG
(PARI) for(n=0, 500, if(isprime(5^n+5*n+1), print1(n", ")))
CROSSREFS
A301638 gives the primes.
Sequence in context: A286279 A125868 A240895 * A031025 A140675 A161532
KEYWORD
nonn,more
AUTHOR
Seiichi Manyama, Mar 25 2018
EXTENSIONS
a(8)-a(11) from Vaclav Kotesovec, Mar 25 2018
STATUS
approved