OFFSET
1,3
COMMENTS
Same as the number of elements of GF(7^n) with trace 2 and subtrace 1. Same as the number of elements of GF(7^n) with trace 3 and subtrace 4. Same as the number of elements of GF(7^n) with trace 4 and subtrace 4. Same as the number of elements of GF(7^n) with trace 5 and subtrace 1. Same as the number of elements of GF(7^n) with trace 6 and subtrace 2.
LINKS
EXAMPLE
a(2;3,4)=1. Let GF(7^2) be defined by the field extension GF(7)[x]/( 3+5b+b^2 ). The one element of GF(7^2) with trace 3 and subtrace 4 is { 5 }.
PROG
(Sage)
def a(n):
ans = 0
for x in GF(7^n):
if x.charpoly().coefficients(sparse=False)[-3:-1]==[2, 1]: ans += 1
return ans # Robin Visser, May 13 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Frank Ruskey and Nate Kube, Aug 19 2002
EXTENSIONS
a(8)-a(12) from Robin Visser, May 13 2024
STATUS
approved