OFFSET
3,4
EXAMPLE
a(3) = 1 because 2^(3 - 1) - 1^2 = 3 is prime with k = 2 and m = 1;
a(4) = 1 because 2^(4 - 1) - 1^2 = 7 is prime with k = 2 and m = 1;
a(5) = 1 because 3^(5 - 2) - 2^3 = 19 is prime with k = 3 and m = 2.
PROG
(PARI) a(n) = {my(k=2, q, v=List([])); if(ispseudoprime(q=2^(n-1)-1), listput(v, q)); while(k^(n-2)>2^k, if(ispseudoprime(q=k^(n-2)-2^k), listput(v, q)); k++); for(m=3, n-2, for(t=2, k-1, if(ispseudoprime(q=t^(n-m)-m^t), listput(v, q)))); #Set(v); } \\ Jinyuan Wang, Feb 24 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Aug 23 2014
EXTENSIONS
Definition and a(7) corrected by Colin Barker, Sep 01 2014
More terms from Jinyuan Wang, Feb 24 2020
STATUS
approved