cp's OEIS Frontend

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.

%I A026069 #8 Sep 14 2019 17:11:51
%S A026069 1,5,13,40,116,342,1002,2941,8629,25333,74405,218659,642955,1891683,
%T A026069 5568867,16403283,48342867,142548639,420546039,1241293314,3665526270,
%U A026069 10829045472,32005684340,94632148659,279909001851,828235716571,2451561077995
%N 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.
%Y A026069 First differences of A025180. Second differences of A014531.
%K A026069 nonn
%O A026069 3,2
%A A026069 _Clark Kimberling_
%E A026069 a(29) corrected by _Sean A. Irvine_, Sep 14 2019