Number of n-step three-sided prudent self-avoiding walks ending on the bottom side of their box.

Terms

a(0) =1a(1) =3a(2) =7a(3) =17a(4) =39a(5) =91a(6) =209a(7) =487a(8) =1135a(9) =2663a(10) =6259a(11) =14769a(12) =34917a(13) =82763a(14) =196489a(15) =467325a(16) =1112941a(17) =2654015a(18) =6335751a(19) =15140525a(20) =36212889a(21) =86685101a(22) =207653983a(23) =497772203a(24) =1193946381a(25) =2865399103a(26) =6880328883a(27) =16528823695a(28) =39725234877a(29) =95514665625