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[parent] examples of 1-automorphic numbers (Example)

Concerning ourselves only with searching for automorphic numbers $ n$ in bases $ 1 < b < 17$ (binary to hexadecimal) and the ranges given by the iterator $ 0 < i < b^3 - 1$, and limiting to $ m = 1$ we find the following results:

First, it is obvious that 1 is a 1-automorphic number regardless of the base.

For the range and limit specified, there are no other 1-automorphic numbers in binary through quinary, bases 7 through 9, 11, 13 and 16.

In base 6, there are 1, 3, 4, 9, 28, 81, 136, and it is easy to verify that $ {3_6}^2 = 13_6$, $ {4_6}^2 = 24_6$, $ {13_6}^2 = 213_6$, $ {44_6}^2 = 3344_6$, etc.

In base 10, these ought to look familiar: 1, 5, 6, 25, 76, 376, 625.

Duodecimal: 1, 4, 9, 64, 81, 513, 1216. Noticing that 4 also appears in the list for base 6, we might wonder if 4 is always 1-automorphic when $ 6\vert b$? The question is moot because the next multiple of 6 is $ 18 > 4^2$, thus in base 18 and any other higher bases, the square of 4 is also a 1-digit number.

Base 14: 1, 7, 8, 49, 148, 344, 2401.

Base 15: 1, 6, 10, 100, 126, 1000, 2376. Base 15 is the smallest odd base $ b$ to have 1-automorphic numbers in the range specified. This should not be taken to imply that it is the smallest odd base to have automorphic numbers at all.



"examples of 1-automorphic numbers" is owned by PrimeFan. [ full author list (2) | owner history (1) ]
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Cross-references: imply, odd, square, multiple, duodecimal, limit, base, number, obvious, iterator, ranges, hexadecimal, binary, bases, automorphic numbers
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This is version 2 of examples of 1-automorphic numbers, born on 2006-10-24, modified 2007-05-23.
Object id is 8470, canonical name is ExamplesOf1AutomorphicNumbers.
Accessed 943 times total.

Classification:
AMS MSC11A63 (Number theory :: Elementary number theory :: Radix representation; digital problems)

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