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A216659 Number of n-digit 9th powers.

%I A216659 #9 Mar 19 2015 21:00:20
%S A216659 2,0,1,0,1,1,1,2,2,3,4,5,6,8,11,13,18,22,30,37,49,63,81,105,135,175,
%T A216659 225,292,377,486,628,811,1048,1353,1748,2257,2916,3766,4863,6281,8113,
%U A216659 10477,13533,17478,22573,29155,37656,48633,62812,81126,104777,135326
%N A216659 Number of n-digit 9th powers.
%H A216659 Alois P. Heinz, <a href="/A216659/b216659.txt">Table of n, a(n) for n = 1..1000</a>
%e A216659 a(1) = 2: 0, 1.
%e A216659 a(3) = 1: 512.
%e A216659 a(5) = 1: 19683.
%e A216659 a(9) = 2: 134217728, 387420489.
%e A216659 a(10) = 3: 1000000000, 2357947691, 5159780352.
%e A216659 a(11) = 4: 10604499373, 20661046784, 38443359375, 68719476736.
%p A216659 r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
%p A216659 a:= n-> r(10^n, 9) -r(10^(n-1), 9) +`if`(n=1, 1, 0):
%p A216659 seq(a(n), n=1..60);
%Y A216659 Column k=9 of A216653.
%K A216659 nonn,base
%O A216659 1,1
%A A216659 _Alois P. Heinz_, Sep 12 2012