a(n) = (A002704(n) - 2)/2.A262584a(n) = (A002704(n) - 2)/2.Terms a(0) =0a(1) =12a(2) =468a(3) =21399a(4) =1065228a(5) =55778796a(6) =3020636340a(7) =167544629316External referencesoeis: A262584