Number of 6-step self-avoiding walks on an n X n square summed over all starting positions.

Terms

a(0) =0a(1) =0a(2) =128a(3) =800a(4) =2112a(5) =4008a(6) =6472a(7) =9504a(8) =13104a(9) =17272a(10) =22008a(11) =27312a(12) =33184a(13) =39624a(14) =46632a(15) =54208a(16) =62352a(17) =71064a(18) =80344a(19) =90192a(20) =100608a(21) =111592a(22) =123144a(23) =135264a(24) =147952a(25) =161208a(26) =175032a(27) =189424a(28) =204384a(29) =219912