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

Terms

a(0) =1a(1) =4a(2) =12a(3) =36a(4) =100a(5) =284a(6) =780a(7) =2172a(8) =5916a(9) =16268a(10) =44100a(11) =120292a(12) =324932a(13) =881500a(14) =2374444a(15) =6416596a(16) =17245332a(17) =46466676a(18) =124658732a(19) =335116620a(20) =897697164a(21) =2408806028a(22) =6444560484a(23) =17266613812a(24) =46146397316a(25) =123481354908a(26) =329712786220a(27) =881317491628