110481

Appears in sequences

• Number of equilateral triangles bounded by the sides and diagonals of a regular 3n-gon.at n=20A238822
• Number of connected labeled transitive relations on an n-set.at n=5A245731
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + n*b(n-1), where a(0) = 1, a(1) = 2, b(0) = 3, b(1) = 4, and (a(n)) and (b(n)) are increasing complementary sequences.at n=18A296288
• Triangular array read by rows: T(n,k) is the number of transitive relations on n labeled nodes with exactly k connected components.at n=16A343882