OFFSET
1,1
COMMENTS
Corresponding values of p^n + 1 are 3, 10, 2198, 3418802, 2073071594, 10779215330, 4163067000501310394, ...
a(16) <= 206874667. - Daniel Suteu, Dec 09 2022
EXAMPLE
a(2) = 3; 3^2 + 1 = 2 * 5.
a(3) = 13; 13^3 + 1 = 2 * 7 * 157.
a(4) = 43; 43^4 + 1 = 2 * 17 * 193 * 521.
PROG
(PARI) a(n) = my(p=2); while (!issquarefree(p^n+1) || omega(p^n+1) != n, p = nextprime(p+1)); p;
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Altug Alkan, Feb 24 2017
STATUS
approved