This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A117583 #21 Oct 18 2022 01:25:00 %S A117583 0,1,3,7,9,16,22,29,35,39,50,57,68,84,100,112,127,151,167 %N A117583 The number of ratios t/(t-1), where t is a triangular number, which factor into primes less than or equal to prime(n). %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. %C A117583 Equivalently, a(n) is the number of quadruples of consecutive prime(n)-smooth numbers. - _Lucas A. Brown_, Oct 04 2022 %H A117583 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/stormer.py">stormer.py</a>. %H A117583 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 A117583 D. H. Lehmer, <a href="http://projecteuclid.org/euclid.ijm/1256067456">On a problem of Størmer</a>, Ill. J. Math., 8 (1964), 57-79. %H A117583 Wikipedia, <a href="http://en.wikipedia.org/wiki/Stormer%27s_theorem">Størmer's theorem</a> %e A117583 The ratios counted by a(3) are 3/2, 6/5, and 10/9. %e A117583 The ratios counted by a(4) are 3/2, 6/5, 10/9, 15/14, 21/20, 28/27, and 36/35. %Y A117583 Cf. A002071, A117582. %K A117583 nonn,hard,more %O A117583 1,3 %A A117583 _Gene Ward Smith_, Apr 02 2006 %E A117583 a(14)-a(18) by _Lucas A. Brown_, Oct 04 2022 %E A117583 a(19) from _Lucas A. Brown_, Oct 16 2022