Number of ways that a directed line (or river) that starts in the south can cross an east-west road n times.
A077014
Number of ways that a directed line (or river) that starts in the south can cross an east-west road n times.
Terms
- a(0) =2a(1) =1a(2) =2a(3) =2a(4) =6a(5) =8a(6) =28a(7) =42a(8) =162a(9) =262a(10) =1076a(11) =1828a(12) =7852a(13) =13820a(14) =61388a(15) =110954a(16) =505878a(17) =933458a(18) =4345660a(19) =8152860a(20) =38608380a(21) =73424650a(22) =352686780a(23) =678390116a(24) =3298016912a(25) =6405031050a(26) =31461151108a(27) =61606881612a(28) =305327366988a(29) =602188541928
External references
- oeis: A077014