2424880domain: NAppears in sequencesPartial sum of usigma is divisible by n, where usigma(n) = A034448(n) and summatory-usigma(n) = A064609(n).at n=17A064611Number of ways to place k nonattacking anassas on an n X n chess board. Triangle T(n,k) read by rows.at n=43A378561