19504

Appears in sequences

• Triangulations of the disk G_{2,n}.at n=7A005498
• Structured heptagonal diamond numbers (vertex structure 5).at n=22A100179
• a(n) = (prime(n)^2 + prime(n+1))/2.at n=43A140511
• Composite numbers k such that k = (product of divisors of k) mod (sum of divisors of k).at n=44A187712
• Square array T(n,m) (n>=0, m>=0) read by antidiagonals downwards giving number of rooted triangulations of type [n,m] up to orientation-preserving isomorphisms.at n=47A262586
• a(n) is the number of edges formed by n-secting the angles of an octagon.at n=27A335771