53836

Appears in sequences

• a(n) = [ 1/(2*t(n+1) - t(n) - t(n+2)) ], where t(n) = tan(Pi/2 - 1/n) satisfies n-1 < t(n) < n for all n >= 1.at n=31A024817
• Base 5 digits are, in order, the first n terms of the periodic sequence with initial period 3,2,1,0.at n=6A037794
• Numerators of continued fraction convergents to sqrt(681).at n=7A042308
• Array read by rows: T(n,k) is the number of nonisomorphic n X n matrices with nonnegative integer entries and row sums k under row and column permutations, (n >= 1, k >= 0).at n=63A318951
• a(n) = Sum_{k = 0..n} (-4)^(n-k)*binomial(n,k)*binomial(3*n+2*k,2*k)* binomial(2*k,k).at n=3A363988