18990

Appears in sequences

• a(n) is the number of partitions of 3n that can be obtained by adding together three (not necessarily distinct) partitions of n.at n=12A002220
• Molien series for full 8 X 8 Siegel modular group H_3 of order 371589120.at n=44A027633
• Expansion of Molien series for 8-dimensional complex Clifford group of genus 3 and order 743178240.at n=22A039946
• Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 9 sites wide.at n=50A058364
• McKay-Thompson series of class 20B for Monster.at n=23A058551
• At stage 1, start with a unit equilateral equiangular triangle. At each successive stage add 3*(n-1) new triangles around outside with edge-to-edge contacts. Sequence gives number of triangles (regardless of size) at n-th stage.at n=34A064412
• Triangle T(n,k) (n >= 2, 1 <= k <= n) read by rows: number of linearly inducible orderings of n points in k-dimensional Euclidean space.at n=39A071223
• Structured triakis octahedral numbers (vertex structure 4).at n=17A100171
• Square array in A071223 read by antidiagonals.at n=69A198889
• Numbers which do not reach zero under either of the iterations: x -> floor(sqrt(x)) * (x - floor(sqrt(x))^2) or y -> ceiling(sqrt(y)) * (ceiling(sqrt(y))^2 - y).at n=21A219963
• Rounded sums of the non-integer cube roots of n, as partitioned by the integer roots: round(Sum_{j=n^3+1..(n+1)^3-1} j^(1/3)).at n=18A248575
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 222", based on the 5-celled von Neumann neighborhood.at n=35A270940
• Number of nX6 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=6A302307
• Number of 7Xn 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=5A302315
• Numbers n such that sigma(n) can be obtained as the base-3 carryless product of 2n and some k.at n=7A325808