a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 1. Also a(n) = T(n,n-1), where T is the array defined in A025177.
A025179
a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is an integer, s(0) = 0, |s(1)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2, s(n) = 1. Also a(n) = T(n,n-1), where T is the array defined in A025177.
Terms
- a(0) =1a(1) =4a(2) =10a(3) =29a(4) =81a(5) =231a(6) =659a(7) =1891a(8) =5443a(9) =15718a(10) =45508a(11) =132067a(12) =384047a(13) =1118820a(14) =3264642a(15) =9539787a(16) =27913083a(17) =81769236a(18) =239794422a(19) =703906719a(20) =2068153899a(21) =6081507831a(22) =17896695831a(23) =52703944965a(24) =155310270101a(25) =457956633826
External references
- oeis: A025179