a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3, s(n) = 2. Also a(n) = T(n,n-2), where T is the array defined in A024996.
A026069
a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3, s(n) = 2. Also a(n) = T(n,n-2), where T is the array defined in A024996.
Terms
- a(0) =1a(1) =5a(2) =13a(3) =40a(4) =116a(5) =342a(6) =1002a(7) =2941a(8) =8629a(9) =25333a(10) =74405a(11) =218659a(12) =642955a(13) =1891683a(14) =5568867a(15) =16403283a(16) =48342867a(17) =142548639a(18) =420546039a(19) =1241293314a(20) =3665526270a(21) =10829045472a(22) =32005684340a(23) =94632148659a(24) =279909001851a(25) =828235716571
External references
- oeis: A026069