n!^3 *sum{k=1 to n} mu(k)/k^3, where mu(k) is the Moebius function A008683.

A068339

n!^3 *sum{k=1 to n} mu(k)/k^3, where mu(k) is the Moebius function A008683.

Terms

    a(0) =1a(1) =7a(2) =181a(3) =11584a(4) =1434176a(5) =311510016a(6) =106474687488

External references