55308

Appears in sequences

• Numbers k such that k and k+1 have the same sum of squarefree divisors, or sqf(k) = sqf(k+1), where sqf(k) = A048250(k).at n=17A063964
• Let f(z) = z^2 + c, then row k lists the expansion of the n-fold composition f(f(...f(0)...)) in rising powers of c.at n=58A137560
• Triangle by rows, related to the numbers of binary trees of height less than n, derived from the Mandelbrot set.at n=42A202019
• Triangle read by rows: T(n,k) is the number of bargraphs of semiperimeter n having width k (n>=2, k>=1).at n=85A271942
• Number of binary search trees (BST) on n nodes which have the same height as the optimal BST.at n=20A328349
• Number T(n,k) of binary search trees of height k having n internal nodes; triangle T(n,k), k>=0, k<=n<=2^k-1, read by columns.at n=36A335920
• Numbers k such that abs(A328258(k)) = abs(A328258(k+1)).at n=35A348586
• Number k such that A033634(k) = A033634(k+1).at n=18A349224
• a(n) is the number of isosceles trapezoids in a triangular grid of side length n.at n=22A389363