A330384 Single-digit numbers in order of appearance in decimal expansions of composite numbers, followed by two-digit numbers in order of appearance, then three-digit numbers and so forth.

4, 6, 8, 9, 1, 0, 2, 5, 7, 3, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86

Offset: 1

Author

David Williams, Dec 12 2019

Keywords

• nonn
• base
• look

Examples

			From _Rémy Sigrist_, Dec 24 2019: (Start)
The first terms, alongside the corresponding composite numbers, are:
  n   a(n)  Composite
  --  ----  ---------
   1     4          4
   2     6          6
   3     8          8
   4     9          9
   5     1         10
   6     0         10
   7     2         12
   8     5         15
   9     7         27
  10     3         30
  11    10         10
  12    12         12
  13    14         14
  ...
  79    99         99
  80    11        110
  81    17        117
  82    19        119
  83    23        123
(End)
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..11000
• Rémy Sigrist, Colored scatterplot of the first 110000 terms (red pixels indicate terms that are prime)
• Rémy Sigrist, PARI program for A330384

Crossrefs

Cf. A002808, A321043, A321128.

Programs

PARI

\\ See Links section.

Extensions

More terms from Rémy Sigrist, Dec 24 2019