518364

Appears in sequences

• Let df(n,k) = Product_{i=0..k-1} (n-i) be the descending factorial and let P(m,n) = df(n-1,m-1)^2*(2*n-m)/((m-1)!*m!). Sequence gives P(7,n).at n=11A132465
• Let S be a strictly monotonic sequence of length 2n and let p and q be subsequences of S each of length n such that the least element belongs to p and every element of S belongs to either p or q. The number of ways to select p such that for any index i the exchange of p(i) and q(i) makes at least one of p and q non-monotonic, is given by a(n).at n=12A137398
• a(n) = 1296*n^2 - 36.at n=19A158737
• Number of ways to place 2 nonattacking amazons (superqueens) on an n X n toroidal board.at n=32A178972
• Numbers k such that A122111(k) [conjugated prime factorization of k] is one of Ore's Harmonic numbers (in A001599).at n=25A336317