19838

Appears in sequences

• Number of ordered quadruples of integers from [ 1,n ] with no common factors between pairs.at n=44A015636
• Otto Haxel's guess for magic numbers of nuclear shells.at n=39A033547
• Number of primitive (period n) bracelet structures using a maximum of five different colored beads.at n=11A056364
• Sum of heights of all 1-watermelons with wall of length 2*n.at n=8A136439
• If 0 <= n <= 3 then a(n) = n(n+1)(n+2)/3, if n >= 4 then a(n) = n(n^2+5)/3.at n=39A162626