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.

1, 5, 13, 40, 116, 342, 1002, 2941, 8629, 25333, 74405, 218659, 642955, 1891683, 5568867, 16403283, 48342867, 142548639, 420546039, 1241293314, 3665526270, 10829045472, 32005684340, 94632148659, 279909001851, 828235716571, 2451561077995

Offset

3,2

Links

Table of n, a(n) for n=3..29.

Crossrefs

First differences of A025180. Second differences of A014531.

Sequence in context: A295913 A272225 A272585 * A054856 A261057 A283456

Adjacent sequences: A026066 A026067 A026068 * A026070 A026071 A026072

Keyword

nonn

Author

Clark Kimberling

Extensions

a(29) corrected by Sean A. Irvine, Sep 14 2019

Status

approved