Number of (s(0),s(1),...,s(n)) such that every s(i) is a nonnegative integer, s(0) = 1, |s(1) - s(0)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also sum of numbers in row n+1 of the array T defined in A026120.
A026135
Number of (s(0),s(1),...,s(n)) such that every s(i) is a nonnegative integer, s(0) = 1, |s(1) - s(0)| = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also sum of numbers in row n+1 of the array T defined in A026120.
Terms
- a(0) =1a(1) =2a(2) =5a(3) =14a(4) =39a(5) =110a(6) =312a(7) =890a(8) =2550a(9) =7334a(10) =21161a(11) =61226a(12) =177575a(13) =516114a(14) =1502867a(15) =4383462a(16) =12804429a(17) =37452870a(18) =109682319a(19) =321563658a(20) =943701141a(21) =2772060618a(22) =8149661730a(23) =23978203662a(24) =70600640796a(25) =208014215066a(26) =613266903927
External references
- oeis: A026135