83790

Appears in sequences

• Number of labeled rooted unordered binary trees (each node has out-degree <= 2).at n=7A036774
• a(1) = 1. a(n) = a(n-1) + a(m), where m is the largest term of the sequence {a(k)} which is less than n.at n=39A133488
• Scaled coefficients of the M. O. Rubinstein polynomials.at n=42A153359
• a(n) = 21*a(n-2) + 7*a(n-3), with a(0)=a(1)=0, a(2)=9.at n=8A215484
• Triangle read by rows: T(m,n) = number of ways of distributing n distinguishable balls into m distinguishable bins of size 2 where empty bins are permitted (m >= 1, 1 <= n <= 2m).at n=47A248844
• Consider the arithmetic derivative of a number x. Take the sum of its digits. Repeat the process deleting the first addendum and adding the previous sum. The sequence lists the numbers that after some iterations reach x.at n=8A269311
• Square array whose entry A(n,k) is the number of labeled rooted trees on a set of size n where each node has at most k neighbors that are further away from the root than the node itself, for n >= 0, k >= 0, read by descending antidiagonals.at n=52A325201
• a(n) = Sum_{k=1..n} Sum_{z=1..n} Sum_{y=1..n} Sum_{x=1..n} [GCD(f(x,y,z), n) = k] * f(x,y,z) * A023900(k), where f(x,y,z) = x^2 + y^2 - z^2.at n=20A373582
• Triangle read by rows: T(n,k) = binomial(n+1,k+1) * binomial(4*n-3*k+1,k) / (n+1), 0<=k<=n.at n=40A391047