a(n) = coefficient of the sqrt(6) term in (1 + sqrt(2) + sqrt(3))^n.

Terms

a(0) =0a(1) =0a(2) =2a(3) =6a(4) =32a(5) =120a(6) =528a(7) =2128a(8) =8960a(9) =36864a(10) =153472a(11) =635008a(12) =2635776a(13) =10922496a(14) =45300736a(15) =187800576a(16) =778731520a(17) =3228696576a(18) =13387309056a(19) =55506722816a(20) =230146834432a(21) =954246856704