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 A211418 #15 Oct 06 2016 10:34:18 %S A211418 1,1,2,6,12,60,60,420,840,2520,2520,27720,13860,180180,360360,360360, %T A211418 720720,12252240,4084080,77597520,38798760,116396280,232792560, %U A211418 5354228880,1338557220,6692786100,13385572200,40156716600,80313433200 %N A211418 a(n) = n!*(floor(n/30))!/((floor(n/2))!*(floor(n/3))!*(floor(n/5))!). %C A211418 For positive real r the ratio of factorials floor((30*r*n))! * (floor(r*n))!/((floor(15*r*n))!*(floor(10*r*n))!*(floor(6*r*n))!) is an integer. The present sequence is the case r = 1/30. The case r = 1 is A211417. %H A211418 Carauleanu Marc, <a href="/A211418/b211418.txt">Table of n, a(n) for n = 0..424</a> %H A211418 P. Bala, <a href="/A211417/a211417_1.txt">Proof of the integrality of A211417 and A211418 </a> %o A211418 (PARI) a(n) = n!*(floor(n/30))!/((floor(n/2))!*(floor(n/3))!*(floor(n/5))!); %o A211418 vector(50, n, a(n-1)) \\ _Altug Alkan_, Oct 02 2015 %Y A211418 Cf. A211417. %K A211418 nonn,easy %O A211418 0,3 %A A211418 _Peter Bala_, Apr 11 2012