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A101234
Numbers k such that 7^k + 5^k - 1 is prime.
0
1, 2, 3, 9, 13, 25, 26, 63, 73, 435, 2245, 2907, 3089, 5615, 20113, 20355, 34127, 47965
OFFSET
1,2
COMMENTS
Terms beyond 435 are (BSW-)pseudoprimes. - Joerg Arndt, Jan 25 2011
a(19) > 60000. - Michael S. Branicky, Oct 27 2024
PROG
(Magma) [n: n in [0..400]|IsPrime(7^n+5^n-1)];
(PARI) for(n=1, 10000, if(isprime(7^n+5^n-1), print1(n, ", "))) /* Joerg Arndt, Jan 25 2011 */
CROSSREFS
Sequence in context: A032486 A123859 A048744 * A233190 A269154 A358829
KEYWORD
nonn,more,changed
AUTHOR
Vincenzo Librandi, Jan 22 2011
EXTENSIONS
a(11)-a(13) from Joerg Arndt, Jan 25 2011
a(14) from Vincenzo Librandi, Jul 28 2020
a(15)-a(16) from Michael S. Branicky, Apr 29 2023
a(17)-a(18) from Michael S. Branicky, Oct 27 2024
STATUS
approved