OFFSET
2,1
COMMENTS
a(n) is the number of primes of the form a*(n^4+1)+b*(n^3+n)+c*n^2 where 1<=a<n, 0<=b<n and 0<=c<n.
LINKS
Robert Israel, Table of n, a(n) for n = 2..250
EXAMPLE
The a(4)=10 5-digit palindromes in base 4 are
257 = 10001_4
373 = 11311_4
409 = 12121_4
461 = 13031_4
509 = 13331_4
787 = 30103_4
839 = 31013_4
887 = 31313_4
907 = 32023_4
991 = 33133_4
MAPLE
f:= proc(n) nops(select(isprime, [seq(seq(seq(i*(n^4+1)+j*(n^3+n)+k*n^2, k=0..n-1), j=0..n-1), i=1..n-1)])) end proc:
map(f, [$2..60]);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert Israel, May 04 2020
STATUS
approved