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%I #9 Oct 22 2013 10:10:15
%S 1,13,25,45,58,88,98
%N If "sumdigit" denotes the sum of the digits of a number then these are the numbers n such that n=sumdigit(sumdigit(n)^sumdigit(n)).
%C Sequence is complete. - _Giovanni Resta_, Mar 21 2013
%e sumdigit(13)=4; 4^4 = 256; sumdigit(256)=13
%p P:=proc(n) local i,j,k,w; for i from 1 by 1 to n do w:=0; k:=i; while k>0 do w:=w+k-trunc(k/10)*10; k:=trunc(k/10); od; k:=w^w; w:=0; while k>0 do w:=w+k-trunc(k/10)*10; k:=trunc(k/10); od; if (i=w) then print(i,w); fi; od; end: P(100);
%t sdQ[n_]:=Module[{sd=Total[IntegerDigits[n]]},n==Total[ IntegerDigits[ sd^sd]]]; Select[Range[100],sdQ] (* _Harvey P. Dale_, Oct 22 2013 *)
%Y Cf. A125526.
%K easy,fini,full,nonn,base
%O 1,2
%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Feb 02 2007
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