A111393 Number of digits in n^3.
1, 1, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7
Offset: 1
Examples
a(10) = 4
Programs
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Maple
A055642 :=proc(n) max(1,ilog10(n)+1) ; end proc: A111393 := proc(n) A055642(n^3) ; end proc: seq(A111393(n),n=1..90) ; # R. J. Mathar, Mar 05 2010
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Mathematica
Array[IntegerLength[#^3]&,110] (* Harvey P. Dale, Dec 26 2014 *)
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PARI
a(n)=if(n==0,1,#digits(n^3)); \\ Joerg Arndt, Mar 30 2014
Formula
a(n) = floor( (3*log_10(n)) + 1).
a(n) = A055642(n^3). [R. J. Mathar, Mar 05 2010]
Extensions
Extended by R. J. Mathar, Mar 05 2010