24 May
2005
24 May
'05
5:06 p.m.
Dan Asimov wrote:
http://www.research.att.com/projects/OEIS?Anum=A089472 Sequence: 2,3,5,7,11,19,43 Name: Number of different values taken by the determinant of a real (0,1)-matrix of order n. ... Q2: Can it be just a coincidence that 1,2,3,7,11,19,43, (all but the fourth term, 5, of A089472) are the first 10 of the 12 "Heegner numbers" (A003173): 1,2,3,7,11,19,43,67,163 ?
Surely it can. The fact that there are only finitely many Heegner numbers means that hardly any elements of A089472 are Heegner numbers, after all. And it scarcely seems credible that the next number would be 67, though 163 mightn't be a great shock. I think this is the Law of Small Numbers in action. -- g