1241293314

Appears in sequences

• 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.at n=19A026069
• a(n) = Sum_{k=0..2n-2} T(n,k) * T(n,k+2), with T given by A025177.at n=9A027259