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A062941 Number of n-digit cubes (0 is included as a single-digit number).

%I A062941 #15 Jun 28 2018 04:45:58
%S A062941 3,2,5,12,25,53,116,249,535,1155,2487,5358,11545,24871,53584,115444,
%T A062941 248715,535841,1154435,2487154,5358411,11544347,24871542,53584111,
%U A062941 115443470,248715414,535841116,1154434691,2487154143,5358411166
%N A062941 Number of n-digit cubes (0 is included as a single-digit number).
%C A062941 Sum of first 3n terms = 10^n.
%H A062941 Harry J. Smith, <a href="/A062941/b062941.txt">Table of n, a(n) for n = 1..300</a>
%e A062941 a(3) = 5 as there are 5 three-digit cubes: 125, 216, 343, 512 and 729.
%p A062941 r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
%p A062941 a:= n-> r(10^n, 3) -r(10^(n-1), 3) +`if`(n=1, 1, 0):
%p A062941 seq(a(n), n=1..40);  # _Alois P. Heinz_, Sep 12 2012
%o A062941 (PARI) { default(realprecision, 300); p=1; b=-1; for (n=1, 300, p*=10; c=b; b=floor((p - 1)^(1/3)); write("b062941.txt", n, " ", b - c) ) } \\ _Harry J. Smith_, Aug 14 2009
%Y A062941 Cf. A062940.
%Y A062941 Column k=3 of A216653.
%K A062941 base,nonn
%O A062941 1,1
%A A062941 _Amarnath Murthy_, Jul 07 2001
%E A062941 Corrected and extended by _Dean Hickerson_, Jul 10 2001
%E A062941 Offset changed from 0 to 1 by _Harry J. Smith_, Aug 14 2009