2-quantum transitions in systems of N>=2 spin 1/2 particles, in columns by combination indices.

Terms

a(0) =1a(1) =6a(2) =24a(3) =4a(4) =80a(5) =40a(6) =240a(7) =240a(8) =15a(9) =672a(10) =1120a(11) =210a(12) =1792a(13) =4480a(14) =1680a(15) =56a(16) =4608a(17) =16128a(18) =10080a(19) =1008a(20) =11520a(21) =53760a(22) =50400a(23) =10080a(24) =210a(25) =28160a(26) =168960a(27) =221760a(28) =73920a(29) =4620