Showing posts with label esthetic. Show all posts
Showing posts with label esthetic. Show all posts

Saturday, 21 September 2024

Aesthetic Numbers


An Aesthetic or Esthetic Number is defined by Numbers Aplenty as a number \(n\)  such that the difference between adjacent digits is 1 when the number is written in base \(b\). Such numbers attracted my attention because 27564, my diurnal age yesterday, is an aesthetic number in base 8 or simply 8-aesthetic because:$$27564_{10}=65654_8$$Let's look firstly at aesthetic numbers in base 10 between 10 and 40000. There are 149 such numbers and they are (permalink):

10, 12, 21, 23, 32, 34, 43, 45, 54, 56, 65, 67, 76, 78, 87, 89, 98, 101, 121, 123, 210, 212, 232, 234, 321, 323, 343, 345, 432, 434, 454, 456, 543, 545, 565, 567, 654, 656, 676, 678, 765, 767, 787, 789, 876, 878, 898, 987, 989, 1010, 1012, 1210, 1212, 1232, 1234, 2101, 2121, 2123, 2321, 2323, 2343, 2345, 3210, 3212, 3232, 3234, 3432, 3434, 3454, 3456, 4321, 4323, 4343, 4345, 4543, 4545, 4565, 4567, 5432, 5434, 5454, 5456, 5654, 5656, 5676, 5678, 6543, 6545, 6565, 6567, 6765, 6767, 6787, 6789, 7654, 7656, 7676, 7678, 7876, 7878, 7898, 8765, 8767, 8787, 8789, 8987, 8989, 9876, 9878, 9898, 10101, 10121, 10123, 12101, 12121, 12123, 12321, 12323, 12343, 12345, 21010, 21012, 21210, 21212, 21232, 21234, 23210, 23212, 23232, 23234, 23432, 23434, 23454, 23456, 32101, 32121, 32123, 32321, 32323, 32343, 32345, 34321, 34323, 34343, 34345, 34543, 34545, 34565, 34567

Here are the frequencies for base 10 numbers being aesthetic in smaller bases in the range from 10 to 40000:

  • base 9 - 165 e.g. 37825 --> 56787
  • base 8 - 171 e.g. 33436 --> 101234
  • base 7 - 164 e.g. 36881 --> 212345
  • base 6 - 188 e.g. 38657 --> 454545
  • base 5 - 182 e.g. 36119 --> 2123434
  • base 4 - 188 e.g. 39867 --> 21232323
  • base 3 - 134 e.g. 36905 --> 1212121212
  • base 2 - 12 e.g. 21845 --> 101010101010101

There are 17, 32, 61, 116, 222, 424, 813, 1556, and 2986 10-aesthetic numbers with 2, 3, 4, 5, 6, 7, 8, 9 and 10 digits respectively. Table 1 shows a screenshot of the Numbers Aplenty website featuring an interesting formula:


Table 1