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%I #17 Jun 19 2019 14:11:39
%S 5848,6884,58480,68840,394062,584800,688400,3940620,5848000,6884000,
%T 39406200,58480000,68840000
%N Like A065759 but where f(n) = 2*n.
%C Numbers of the form 5848*10^k, 6884*10^k, 394062*10^k, with k>=0, belong to the sequence.
%e 5848 = concat(5*848) = concat(58*48) = concat(584*8) and (5*848 + 58*48 + 584*8) = 11696 = 2*5848.
%p P:=proc(q) local a,k,n; for n from 1 to q do a:=0;
%p for k from 1 to ilog10(n) do a:=a+(n mod 10^k)*trunc(n/10^k); od;
%p if a/n=2 then print(n); fi; od; end: P(10^9);
%t Select[Range[10^6], Function[n, Module[{a = {}, e = IntegerLength@ n - 1, k}, Do[AppendTo[a, # (n - #*10^(e - k)) &@ Floor[n/10^(e - k)]], {k, 0, e - 1}]; Total@ a] == 2 n]] (* _Michael De Vlieger_, Jan 04 2017 *)
%Y Cf. A065759, A280445, A280447.
%K nonn,base,more
%O 1,1
%A _Paolo P. Lava_, Jan 03 2017
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