19241

Appears in sequences

• Number of rooted ternary trees with n nodes; number of n-carbon alkyl radicals C(n)H(2n+1) ignoring stereoisomers.at n=14A000598
• Nonprime numbers k such that sum of aliquot divisors of k is a cube.at n=42A048698
• Numerators of a(n+1) = Sum_{k=1..n} a'(n/k), a(1)=1, where a'(x)=a(x) if x integer and is linearly interpolated otherwise.at n=15A071795
• a(1) = a(2) = 1; for n>2, a(n+1) = a(n) + a(n-1) iff n is prime, otherwise a(n+1) = a(n) + 1.at n=45A113050
• Iterates of A122237 starting from the initial value 8.at n=7A179756
• Floor-Sqrt transform of Lucas numbers (A000032).at n=41A192660
• The 300-degree spoke (or ray) of a hexagonal spiral of Ulam.at n=40A244804
• Number of permutations p of [n] such that p(i) > p(i+1) iff i == 2 (mod 3).at n=10A249583
• Number of set partitions of [n] such that the difference between each element and its block index is a multiple of seven.at n=25A274840
• a(n) = a(n-1) + a(n-2) + a(n-3) - 2*a(n-4) for n >= 5, where a(0) = 2, a(1) = 4, a(2) = 5, a(3) = 8, a(4) = 11.at n=22A288523
• Where the ratio A235027(n)/n obtains record values.at n=15A290078
• Number of linear extensions of a poset whose Hasse diagram consists of n binary shrubs with type S_n joins.at n=3A293953
• Number of integer partitions of n whose number of submultisets is greater than n.at n=37A325831
• Number of integer partitions of n whose number of submultisets is greater than or equal to n.at n=37A325832
• a(0) = 1 by convention; for n>0, a(n) is the number of points in the n-th figure shown in A255011 (meaning the figure with 4n points on the perimeter).at n=8A331449
• Triangle read by rows: T(n,m) (n >= m >= 1) = number of vertices formed by drawing the lines connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares.at n=35A331453
• Table read by antidiagonals: Place k equally spaced points on each side of a regular n-gon and join every pair of the n*(k+1) boundary points by a chord; T(n,k) (n >= 3, k >= 0) gives the number of vertices in the resulting planar graph.at n=37A367322