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 A130065 #14 Nov 27 2020 04:51:00
%S A130065 1,2,3,4,5,4,7,8,9,4,11,8,13,4,9,16,17,12,19,8,9,4,23,16,25,4,27,8,29,
%T A130065 12,31,32,9,4,25,24,37,4,9,16,41,12,43,8,27,4,47,32,49,20,9,8,53,36,
%U A130065 25,16,9,4,59,24,61,4,27,64,25,12,67,8,9,20,71,48,73,4,45,8,49,12,79,32,81
%N A130065 a(n) = (n / GreatestPrimeFactor(n)) * SmallestPrimeFactor(n).
%H A130065 Reinhard Zumkeller, <a href="/A130065/b130065.txt">Table of n, a(n) for n = 1..10000</a>
%F A130065 a(n) = n*A020639(n)/A006530(n) = A052126(n)*A020639(n);
%F A130065 a(n) <= n; a(n) = n iff n is a prime power: a(A000961(n)) = A000961(n);
%F A130065 a(A001221(n)) <= A001221(n); a(A001222(n)) = A001222(n);
%F A130065 a(n) = A130064(n) - n*A046665(n)*A074320(n)/A066048(n) = A000290(n)/A130064(n).
%t A130065 a[n_] := Module[{ps = First /@ FactorInteger[n]}, n * First[ps] / Last[ps]]; Array[a, 100] (* _Amiram Eldar_, Nov 27 2020 *)
%o A130065 (PARI) a(n) = if (n==1, 1, my(f=factor(n)[,1]~); n*vecmin(f)/vecmax(f)); \\ _Michel Marcus_, Nov 27 2020
%Y A130065 Cf. A000290, A001221, A001222, A006530, A000961, A020639, A046665, A052126, A066048, A074320, A130064.
%K A130065 nonn
%O A130065 1,2
%A A130065 _Reinhard Zumkeller_, May 05 2007