21392

Appears in sequences

• Expansion of e.g.f. sec(sinh(x)*tan(x)) (only even powers).at n=4A012552
• Number of primitive (aperiodic) reversible string structures with n beads using exactly five different colors.at n=9A056339
• Triangle in which row n lists the coefficients in Product_{k=1..n} (1 + k*x + x^2), for n>=0, as read by rows.at n=54A249790
• Triangle in which row n lists the coefficients in Product_{k=1..n} (1 + k*x + x^2), for n>=0, as read by rows.at n=58A249790
• Triangle read by rows: T(n,k) = number of partial idempotent mappings (of an n-chain) with (right) waist exactly k.at n=42A258579
• Triangle read by rows: T(n,k) = number of primitive (aperiodic) reversible string structures with n beads using exactly k different colors.at n=49A276544
• The number of non-equivalent distinguishing coloring partitions of the path on n vertices (n>=1) with exactly k parts (k>=1). Regular triangle read by rows: the rows are indexed by n, the number of vertices of the path, and the columns are indexed by k, the number of parts.at n=49A309748