18298

Appears in sequences

• Number of atoms in a decahedron with n shells.at n=28A004068
• Expansion of 1/((1-x)(1-3x)(1-6x)).at n=5A016211
• Surround numbers of an n X 1 rectangle.at n=11A060633
• Numbers n such that h(n) = 2 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.)at n=33A078419
• Stirling-like number triangle defined by sequence A000217.at n=30A080248
• Successive powers of the matrix A=[1,2;3,4] written by rows in groups of 4.at n=23A100638
• a(1) = 1; a(n) = sum of previous terms a(k) such that a(k) + n is prime.at n=58A108867
• Number of rooted trees with total weight n, where the weight of a node at height k is k (with the root considered to be at level 1).at n=52A117357
• Irregular triangle read by rows: T(n,k) is the number of necklaces of n 1's, n -1's, and k 0's such that no two adjacent elements are equal.at n=57A283615
• T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.at n=46A284075
• Number of 2Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.at n=8A284076
• Number of ways to place 3 points on an n X n point grid so that no point is equally distant from two other points on the same row or the same column.at n=6A296997