1309568domain: NAppears in sequencesPoupard's triangle: triangle of numbers arising in enumeration of binary trees.at n=39A008301Let r, s, t, u be four permutations of the set { 1, 2, 3, ..., n }; a(n) = minimal value of Sum_{i=1..n} r(i)*s(i)*t(i)*u(i).at n=34A070736Left half of Poupard's triangle, A008301.at n=24A210108