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 A259365 Numbers n such that phi(Rev(n)) - phi(n) = n. 0

%I

%S 28,139872,2764928,34141176,329774256

%N Numbers n such that phi(Rev(n)) - phi(n) = n.

%C a(6) > 3*10^10. - _Giovanni Resta_, Jun 26 2015

%F Solutions of the equation A000010( A004086(n) ) - A000010(n) = n.

%e phi(82) - phi(28) = 40 - 12 = 28;

%e phi(278931) - phi(139872) = 184032 - 44160 = 139872; etc.

%p with(numtheory): T:=proc(w) local x,y,z; x:=w; y:=0;

%p for z from 1 to ilog10(x)+1 do

%p y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:

%p P:=proc(q) local a,j,k,n; for n from 1 to q do

%p if phi(T(n))-phi(n)=n then print(n); fi; od; end: P(10^9);

%Y Cf. A000010, A004086, A097647.

%K nonn,more,base

%O 1,1

%A _Paolo P. Lava_, Jun 25 2015

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Last modified May 27 10:31 EDT 2020. Contains 334655 sequences. (Running on oeis4.)