23973

Appears in sequences

• Number of 5-tuples of different integers from [ 2,n ] with no common factors among triples.at n=25A015649
• a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049723.at n=35A049726
• Least number m such that phi(m-6n) = phi(m) = phi(m+6n) and m is not divisible by n.at n=4A217068