Number of self-avoiding walks of n steps on a Manhattan square lattice.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =14a(5) =26a(6) =48a(7) =88a(8) =154a(9) =278a(10) =500a(11) =900a(12) =1576a(13) =2806a(14) =4996a(15) =8894a(16) =15564a(17) =27538a(18) =48726a(19) =86212a(20) =150792a(21) =265730a(22) =468342a(23) =825462a(24) =1442866a(25) =2535802a(26) =4457332a(27) =7835308a(28) =13687192a(29) =24008300