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 A195458 #19 Feb 17 2023 07:39:07
%S A195458 1,1,1,2,4,8,16,32,96,288,864,2592,7776,23328,69984,279936,1119744,
%T A195458 4478976,17915904,71663616,286654464,1146617856,4586471424,
%U A195458 18345885696,91729428480,458647142400,2293235712000,11466178560000,57330892800000,286654464000000
%N A195458 a(n) = floor(sqrt(n)) * a(n-1), starting with 1.
%C A195458 a(n) = r(n+2)/sqrt(2); r(1) = sqrt(2); r(n) = r(n-1)/sqrt(n-1) if r(n-1) is a square else r(n) = r(n-1)*floor(sqrt(n-1).
%C A195458 A variation of Recamán's A008336.
%F A195458 a(n) = Product_{k=1..n} floor(sqrt(k)). - _Ridouane Oudra_, Feb 16 2023
%p A195458 r := proc(n) option remember; if n = 1 then sqrt(2)
%p A195458 elif type(r(n-1),square) then r(n-1)/sqrt(n-1)
%p A195458 else r(n-1)*floor(sqrt(n-1)) fi end:
%p A195458 A195458 := proc(n) r(n+2)/sqrt(2) end:
%t A195458 a[1] = 1;
%t A195458 a[n_] := a[n] = Floor[Sqrt[n]] a[n - 1]
%t A195458 Table[a[n], {n, 20}] (* _David Callan_, Aug 14 2013 *)
%Y A195458 Cf. A008336.
%K A195458 nonn
%O A195458 1,4
%A A195458 _Peter Luschny_, Sep 18 2011
%E A195458 Better name from _David Callan_, Aug 14 2013