a(n) = (1/(7*n)) * Sum_{d|n} mu(n/d) * binomial(7*d,d).
A346581
a(n) = (1/(7*n)) * Sum_{d|n} mu(n/d) * binomial(7*d,d).
Terms
- a(0) =1a(1) =6a(2) =63a(3) =728a(4) =9275a(5) =124866a(6) =1753073a(7) =25365600a(8) =375677595a(9) =5667202850a(10) =86775157139
External references
- oeis: A346581