%I A117583
%S A117583 0,1,3,7,9,16,22,29,35,39,50,57,68
%N A117583 For successive primes p, the number of ratios t(n)/(t(n)-1), where t(n)=n(n+1)/
               2 is the n-th triangular number, which factor into primes less than 
               or equal to p.
%C A117583 As in the case of square numerators, triangular numerators of superparticular 
               ratios m/(m-1) factorizable only up to a relatively small prime p 
               are relatively common.
%D A117583 E. F. Ecklund and R. B. Eggleton, Prime factors of consecutive integers, 
               Amer. Math. Monthly, 79 (1972), 1082-1089.
%D A117583 D. H. Lehmer, On a problem of Stormer, Ill. J. Math., 8 (1964), 57-69.
%Y A117583 Cf. A002071, A117582.
%Y A117583 Sequence in context: A128539 A057463 A118258 this_sequence A126106 A064194 
               A036978
%Y A117583 Adjacent sequences: A117580 A117581 A117582 this_sequence A117584 A117585 
               A117586
%K A117583 hard,nonn
%O A117583 1,3
%A A117583 Gene Ward Smith (genewardsmith(AT)gmail.com), Apr 02 2006