34611

Appears in sequences

• a(0)=1 if n>0 a(n)=(-1)^(n+1)/(2n+1) * Sum_{k=0..n} 4^(5k)*B(2k)*C(2n+1,2k) where B(k) denotes the k-th Bernoulli number.at n=2A076573
• Number of nX4 binary arrays with rows and columns lexicographically nondecreasing and column sums nondecreasing.at n=7A266424
• Irregular triangle read by rows: T(n,k) = number of k-sided polygons formed when connecting infinite lines between all vertices and all points that divide the sides of an equilateral triangle into n equal parts, for k = 3, 4, ..., max_k.at n=52A346446