OFFSET
1,2
LINKS
Project Euler, Problem 735. Divisors of 2n^2
EXAMPLE
a(15)=8 because the divisors of 2*15^2=450 which are <=15 are 1, 2, 3, 5, 6, 9, 10 and 15.
MAPLE
PROG
(PARI) a(n) = sumdiv(2*n^2, d, d <= n); \\ Michel Marcus, Mar 21 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Mar 20 2023
STATUS
approved