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 A227848 #20 Dec 23 2018 14:38:47
%S A227848 1,9,71,120,331,393,728,1223,3697,4123,6791,7391,23911,25099,35287,
%T A227848 86442,86716,118034,292411,352970,527255,606425
%N A227848 Numbers n such that Sum_{i=1..n} (i')^i == 0 (mod n), where i' is the arithmetic derivative of i.
%C A227848 a(19) > 200000. - _Giovanni Resta_, Aug 01 2013
%e A227848 1'^1 + 2'^2 + 3'^3 + 4'^4 + 5'^5 + 6'^6 + 7'^7 + 8'^8 + 9'^9 = 0^1 + 1^2 + 1^3 + 4^4 + 1^5 + 5^6 + 1^7 + 12^8 + 6^9 = 440075277 and 440075277 / 9 = 48897253.
%p A227848 with(numtheory); ListA227848:=proc(q) local a, n, p; a:=0;
%p A227848 for n from 1 to q do a:=a+(n*add(op(2, p)/op(1, p), p=ifactors(n)[2]))^n;
%p A227848 if a mod n=0 then print(n); fi; od; end: ListA227848(10^6);
%t A227848 d[n_] := d[n] = n* Total[Apply[#2/#1 &, FactorInteger[n], {1}]]; Reap[For[n = 1, n <= 2*10^5, n++, If[Mod[Sum[d[k]^k, {k, 1, n}], n] == 0, Print[n]; Sow[n]]]][[2, 1]] (* _Jean-François Alcover_, Feb 21 2014 *)
%Y A227848 Cf. A003415, A227502.
%K A227848 nonn,more
%O A227848 1,2
%A A227848 _Paolo P. Lava_, Aug 01 2013
%E A227848 a(16)-a(18) from _Giovanni Resta_, Aug 01 2013
%E A227848 a(19)-a(22) from _Bert Dobbelaere_, Dec 23 2018