Sum of squares of end-to-end distances for self-avoiding walks on the Manhattan lattice.

Terms

a(0) =1a(1) =6a(2) =20a(3) =56a(4) =141a(5) =328a(6) =732a(7) =1584a(8) =3339a(9) =6894a(10) =14018a(11) =28132a(12) =55819a(13) =109668a(14) =213711a(15) =413520a(16) =795041a(17) =1519632a(18) =2890050a(19) =5471864a(20) =10317249a(21) =19378344a(22) =36273795a(23) =67690580a(24) =125950933a(25) =233715516a(26) =432618758a(27) =798985468a(28) =1472443438a(29) =2708024388