132640

Appears in sequences

• Triangle read by rows: T(n,k) is the number of single loop solutions formed by n proper arches (connecting odd vertices to even vertices in the range 1 to 2n) above the x axis, k of which connect an odd vertex to a higher even vertex, with a rainbow of n arches below the x axis.at n=49A244312
• Number of possible chess games at the end of the n-th ply starting without knights.at n=4A285875
• Numbers k > 0 that set a new record for the closeness of 4*Pi*k^2 to an integer.at n=11A297840
• a(n) = Sum_{k=1..n} mu(k) * (floor(n/k)^4 - floor((n-1)/k)^4).at n=32A344597