a(n) = lcm(n^2, swinging_factorial(n)).

Terms

a(0) =0a(1) =1a(2) =4a(3) =18a(4) =48a(5) =150a(6) =180a(7) =980a(8) =2240a(9) =5670a(10) =6300a(11) =30492a(12) =11088a(13) =156156a(14) =168168a(15) =257400a(16) =1647360a(17) =3719430a(18) =3938220a(19) =17551820a(20) =18475600a(21) =81477396a(22) =85357272a(23) =373173528a(24) =389398464a(25) =1690097500a(26) =1757701400a(27) =7582037400a(28) =3931426800a(29) =33738060600