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A370663
Numbers k such that (9^k + 9*k)/9 is prime.
1
1, 2, 4, 8, 10, 28, 1348, 1424, 12838
OFFSET
1,2
COMMENTS
If it exists, a(10) > 50000.
PROG
(PARI) is(n) = ispseudoprime(9^(n-1)+n)
CROSSREFS
Sequence in context: A376681 A056654 A365002 * A020950 A056386 A331027
KEYWORD
nonn,hard,more
AUTHOR
Hugo Pfoertner, Feb 27 2024
STATUS
approved