169209

Appears in sequences

• a(n) = 3a(n-1) + 3a(n-2). a(0) = 1, a(1) = 4.at n=9A125145
• Triangle read by rows: T(n,k) is the number of sequences of length n on the alphabet {0,1,2,3}, containing k subsequences 00 (0<=k<=n-1).at n=37A128235
• Coefficients of numerator of recursively defined rational function: p(x,3)=x*(x^2 + 6*x + 1)/(1 - x)^4; p(x, n) = 2*x*D[p(x, n - 1), x] - p(x,n-2).at n=30A166349
• Coefficients of numerator of recursively defined rational function: p(x,3)=x*(x^2 + 6*x + 1)/(1 - x)^4; p(x, n) = 2*x*D[p(x, n - 1), x] - p(x,n-2).at n=33A166349
• Number of n X 9 binary matrices with no 2 X 2 block having four 1's.at n=1A181252
• Number of rooted fullerenes with n faces, where "rooted" means that one triple (v,e,f) is distinguished, where v is a vertex, e is an edge on that vertex and f is a face on that edge.at n=17A203977