Denominator of Sum_{k=1..n} 1/A045542(k).

Terms

a(0) =3a(1) =21a(2) =168a(3) =280a(4) =210a(5) =1365a(6) =42315a(7) =8463a(8) =45136a(9) =406224a(10) =253890a(11) =310310a(12) =744744a(13) =744744a(14) =94582488a(15) =661416a(16) =110236a(17) =21496020a(18) =924328860a(19) =7394630880a(20) =894750336480