A210436 Number of digits in 6^n.
1, 1, 2, 3, 4, 4, 5, 6, 7, 8, 8, 9, 10, 11, 11, 12, 13, 14, 15, 15, 16, 17, 18, 18, 19, 20, 21, 22, 22, 23, 24, 25, 25, 26, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 36, 36, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45, 46, 46, 47, 48, 49, 50, 50, 51, 52, 53
Offset: 0
Examples
a(4) = 4 because 6^4 = 1296, which has 4 digits. a(5) = 4 because 6^5 = 7776, which has 4 digits.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..1000
Programs
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Magma
[#Intseq(6^n): n in [0..67]]; // Bruno Berselli, Mar 22 2012
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Maple
a:= n-> length(6^n): seq (a(n), n=0..100); # Alois P. Heinz, Mar 22 2012
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Mathematica
Table[Length[IntegerDigits[6^n]], {n, 0, 99}] (* Alonso del Arte, Mar 22 2012 *)
Formula
a(n) = A055642(A000400(n)) = A055642(6^n) = floor(log_10(10*(6^n))). - Jonathan Vos Post, Mar 23 2012