Number of self-avoiding paths with n steps on a triangular lattice in the strip Z x {0,1}.

Terms

a(0) =1a(1) =4a(2) =12a(3) =30a(4) =70a(5) =158a(6) =352a(7) =780a(8) =1724a(9) =3806a(10) =8398a(11) =18526a(12) =40864a(13) =90132a(14) =198796a(15) =438462a(16) =967062a(17) =2132926a(18) =4704320a(19) =10375708a(20) =22884348a(21) =50473022a(22) =111321758a(23) =245527870a(24) =541528768a(25) =1194379300a(26) =2634286476a(27) =5810101726a(28) =12814582758