OFFSET
1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
PROG
(PARI) a(n) = my(p=prime(n), i=0); while(1, if(!ispseudoprime(2*p^3-1), return(i), p=2*p^3-1; i++))
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Feb 26 2017
STATUS
approved