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A355170
The composite numbers in order of appearance in A173395.
0
4, 6, 8, 9, 10, 12, 15, 16, 14, 18, 20, 21, 24, 25, 28, 30, 27, 32, 35, 36, 22, 40, 42, 33, 45, 48, 49, 26, 44, 50, 54, 56, 39, 55, 60, 63, 64, 52, 66, 70, 72, 65, 77, 80, 81, 34, 78, 84, 88, 90, 51, 75, 91, 96, 99, 100, 38, 68, 98, 104, 108, 110, 57, 85, 105
OFFSET
1,1
COMMENTS
This sequence can be generated by removing duplicates from A173395. As such, every number in this sequence is composite, and every composite number appears in this sequence.
This gives a method of enumerating the composite numbers.
EXAMPLE
This sequence can be generated by reading along the diagonals of the multiplication table with headers starting at 2, skipping any number that has already been seen:
4 6 8 10 12 ...
6 9 12 15 18 ...
8 12 16 20 24 ...
10 15 20 25 30 ...
12 18 24 30 36 ...
...
CROSSREFS
Cf. A173395, A257471 (similar construction).
Sequence in context: A109289 A066071 A306307 * A248010 A067013 A141607
KEYWORD
nonn,easy
AUTHOR
Denver Massey, Jun 22 2022
STATUS
approved