50073domain: NAppears in sequencesa(n) = Sum_{i=1..n, j=1..n, gcd(i,j)=1} (n+1-i)*(n+1-j).at n=22A115004Number of 2 X 2 matrices M with all terms in {1,...,n} and permanent(M) >= n.at n=15A212240a(n) = A115004(2n+1).at n=11A331759Number of primes between pairs of consecutive highly composite numbers (A002182).at n=39A333725