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

Terms

a(0) =1a(1) =3a(2) =7a(3) =18a(4) =45a(5) =113a(6) =283a(7) =709a(8) =1775a(9) =4442a(10) =11111a(11) =27781a(12) =69433a(13) =173468a(14) =433229a(15) =1081609a(16) =2699521a(17) =6735586a(18) =16801355a(19) =41898736a(20) =104460505a(21) =260378007a(22) =648878481a(23) =1616720044a(24) =4027390409a(25) =10030782405a(26) =24978849433a(27) =62192878443a(28) =154825778335