17539200

Appears in sequences

• One half of third column of triangle A075181.at n=7A075183
• Number of "ups" and "downs" in the permutations of [n] if either a previous counted "up" ("down") or a "void" precedes an "up" ("down") which then will be counted also.at n=8A120928
• Triangular array: row n gives the coefficients of the polynomial p(n,x) defined in Comments.at n=37A249253