OFFSET
0,6
COMMENTS
The primality test for Proth numbers can be used. - Thomas Ordowski, Apr 13 2019
FORMULA
a(n) = min{a : a > 0 and (a*2^2^n)! == -1 (mod a*2^2^n+1)}.
PROG
(PARI) isok(k, n) = isprime(k*2^(2^n) + 1);
a(n) = my(k=1); while (!isok(k, n), k++); k; \\ Michel Marcus, Apr 15 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alar Leibak (aleibak(AT)cyber.ee)
EXTENSIONS
a(11)-a(17) from Donovan Johnson, Mar 26 2010
a(18)-a(19) from Donovan Johnson, Jan 14 2012
Name edited by Thomas Ordowski, Apr 13 2019
STATUS
approved