%N For successive primes p, the number of ratios of the form n^2/(n^2-1) which factor into primes less than or equal to p.
%C By a theorem of Størmer, the number of ratios m/(m-1) factoring into primes only up to p is finite. A proportion of these have square denominators.
%H E. F. Ecklund and R. B. Eggleton, <a href="http://www.jstor.org/stable/2317422">Prime factors of consecutive integers</a>, Amer. Math. Monthly, 79 (1972), 1082-1089.
%H D. H. Lehmer, <a href="http://projecteuclid.org/euclid.ijm/1256067456">On a problem of Størmer</a>, Ill. J. Math., 8 (1964), 57-79.
%Y Cf. A002071, A117583.
%A _Gene Ward Smith_, Apr 02 2006