On Sunday, July 6, 2003, at 03:18 am, David Wilson wrote:
A033677 is the smallest divisor of n >= sqrt(n). The Maple program given for this looks quite inefficient. It appears to obtain the divisors of n, then compare them all to the sqrt(n). A033677(n) will be the central element or larger of two central elements of the sorted list of divisors of n.
Yes, or the minimal divisor d such that n/d <= d. (But I don't see any way to use it to help answer the original question.) I've been contemplating the infinite rectangular array of which A027424 is the main diagonal: the (m,n) entry is the number of distinct products ij with 1<=i<=m, i<=j<=n: 1 2 3 4 5 6 7 8 9 10 2 3 5 6 8 9 11 12 14 15 3 5 6 8 11 12 15 17 18 20 4 6 8 9 13 15 19 20 22 24 5 8 11 13 14 17 22 24 27 28 6 9 12 15 17 18 24 27 30 32 7 11 15 19 22 24 25 29 33 36 8 12 17 20 24 27 29 30 35 39 9 14 18 22 27 30 33 35 36 41 10 15 20 24 28 32 36 39 41 42 Couldn't get a recursion for this one either thought... --Michael Kleber kleber@brandeis.edu