OFFSET
1,1
COMMENTS
a(n) divides A244509(n).
LINKS
Gregor Olsavsky, Groups formed from 2 X 2 matrices over Z_p, Mathematics Magazine, Vol. 63, No. 4 (Oct., 1990), pp. 269-272.
FORMULA
a(n) = p*(p-1)^2 where p = prime(n).
EXAMPLE
Over Z_2, there are only two invertible upper triangular 2 X 2 matrices: [[1,0],[0,1]] and [[1,1],[0,1]] so a(1) = 2.
PROG
(Sage) [nth_prime(p)*(nth_prime(p)-1)^2 for p in [1..35]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Tom Edgar, Mar 22 2016
STATUS
approved