Number of n-step point-symmetrical self-avoiding walks on the square lattice.

Terms

a(0) =4a(1) =4a(2) =12a(3) =12a(4) =36a(5) =36a(6) =100a(7) =100a(8) =284a(9) =276a(10) =780a(11) =764a(12) =2148a(13) =2084a(14) =5868a(15) =5692a(16) =15956a(17) =15436a(18) =43300a(19) =41812a(20) =117100a(21) =112916a(22) =316076a(23) =304524a(24) =851612a(25) =819372a(26) =2290932a(27) =2203132a(28) =6154284a(29) =5912572