Number of n-step two-sided prudent self-avoiding walks.

Terms

a(0) =1a(1) =4a(2) =10a(3) =26a(4) =66a(5) =168a(6) =426a(7) =1078a(8) =2722a(9) =6862a(10) =17274a(11) =43432a(12) =109086a(13) =273734a(14) =686334a(15) =1719604a(16) =4305666a(17) =10774550a(18) =26948142a(19) =67367456a(20) =168337622a(21) =420472716a(22) =1049866442a(23) =2620488898a(24) =6538734758a(25) =16310909604a(26) =40676600026a(27) =101414764862a(28) =252787228590a(29) =629960214066