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 A190650 #14 Oct 20 2024 02:34:28 %S A190650 1,2,3,8,10,12,14,16,27,30,33,36,39,42,45,128,136,144,152,160,168,176, %T A190650 184,192,250,260,270,280,290,300,310,320,330,340,350,432,444,456,468, %U A190650 480,492,504,516,528,540,552,564,576,686,700,714,728,742,756,770,784,798,812,826,840,854,868,882,1024,1040,1056,1072,1088,1104,1120,1136,1152,1168,1184,1200,1216,1232,1248,1264,1280 %N A190650 Product of iterated integral part of square root. %C A190650 a(n) = n * f(n) * f(f(n)) * ..., where f(n) = floor(sqrt(n)). Although this is written as an infinite product, all but finitely many terms are 1. %H A190650 Rémy Sigrist, <a href="/A190650/b190650.txt">Table of n, a(n) for n = 1..10000</a> %F A190650 a(1) = 1; for n>1, a(n) = n*a(floor(sqrt(n))). %F A190650 a(n) <= n^2/2 for n > 1. Equality holds for n = 2^2^k. %e A190650 a(1) = 1, a(2) = 2*1, a(3) = 3*1, a(4) = 4*2*1, a(5) = 5*2*1, .... %o A190650 (PARI) a(n)=local(r);r=n;while((n=sqrtint(n))>1,r*=n);r %Y A190650 Cf. A000196, A007590, A001146, A190668. %K A190650 nonn,easy %O A190650 1,2 %A A190650 _Franklin T. Adams-Watters_, May 16 2011