Number of ballot sequences of length n with exactly 6 fixed points.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =3a(9) =9a(10) =29a(11) =99a(12) =357a(13) =1350a(14) =5334a(15) =21912a(16) =93352a(17) =410988a(18) =1866492a(19) =8720924a(20) =41866020a(21) =206085480a(22) =1039120104a(23) =5358418224a(24) =28235017104a(25) =151838491408a(26) =832730775888