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 A282771 #9 Mar 02 2017 03:40:22 %S A282771 0,64,432,2916,19683,50000,337500,2278125,13176688,39062500,88942644, %T A282771 263671875,600362847,10294287500,30517578125,69486440625, %U A282771 2712892291396,4564986729776,8042412109375,18312022966923,30813660425988,207992207875419,2119447102653125,3566395882637500 %N A282771 Integers that are one third of their arithmetic derivatives. %C A282771 All integers of the form p^p*q^q*r^r, with p, q and r primes, are in the sequence. %F A282771 Solution of the equation n’ = 3*n. %e A282771 337500 = 2^2*3^3*5^5, 337500’ = 1012500 and 337500 = 3*1012500. %p A282771 with(numtheory): with(combinat): P:=proc(q) local a,k,n,x,y; %p A282771 x:=[]; y:=[]; for n from 1 to q do for k from 1 to 3 do x:=[op(x),ithprime(n)^ithprime(n)]; od; od; %p A282771 a:=choose(x,3); for k from 1 to nops(a) do y:=[op(y),convert(a[k],`*`)]; od; y:=sort([op(y)]); print(0); %p A282771 for k from 1 to 100 do print(y[k]); od; end: P(10); %Y A282771 Cf. A003415, A072873, A165558. %K A282771 nonn %O A282771 1,2 %A A282771 _Paolo P. Lava_, Mar 02 2017