n*[n/2]*[n/3], where [] = floor.

Terms

a(0) =0a(1) =0a(2) =0a(3) =3a(4) =8a(5) =10a(6) =36a(7) =42a(8) =64a(9) =108a(10) =150a(11) =165a(12) =288a(13) =312a(14) =392a(15) =525a(16) =640a(17) =680a(18) =972a(19) =1026a(20) =1200a(21) =1470a(22) =1694a(23) =1771a(24) =2304a(25) =2400a(26) =2704a(27) =3159a(28) =3528a(29) =3654