Number of 4-cycles in the n-tetrahedral graph.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =90a(5) =540a(6) =1995a(7) =5775a(8) =14280a(9) =31500a(10) =63630a(11) =119790a(12) =212850a(13) =360360a(14) =585585a(15) =918645a(16) =1397760a(17) =2070600a(18) =2995740a(19) =4244220a(20) =5901210a(21) =8067780a(22) =10862775a(23) =14424795a(24) =18914280a(25) =24515700a(26) =31439850a(27) =39926250a(28) =50245650a(29) =62702640