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A338461
Lexicographically earliest divisibility sequence consisting only of distinct nonprime numbers.
2
1, 4, 6, 8, 9, 12, 10, 16, 18, 36, 14, 24, 15, 20, 54, 32, 21, 72, 22, 144, 30, 28, 25, 48, 27, 60, 90, 40, 26, 108, 33, 64, 42, 84, 180, 216, 34, 44, 120, 288, 35, 240, 38, 56, 162, 100, 39, 96, 50, 324, 126, 360, 45, 720, 252, 80, 66, 52, 46, 432, 49, 132
OFFSET
1,2
COMMENTS
This sequence is a permutation of the nonprime numbers (A018252).
FORMULA
a(p) < a(n) for any prime number p and n > p.
EXAMPLE
For n = 1:
- we choose a(1) = 1.
For n = 2:
- a(2) must be divisible by a(1) = 1,
- we choose a(2) = 4.
For n = 3:
- a(3) must be divisible by a(1) = 1,
- we choose a(3) = 6.
For n = 4:
- a(4) must be divisible by a(1) = 1 and a(2) = 4,
- we choose a(4) = 8.
PROG
(PARI) See Links section.
CROSSREFS
See A338219 for a similar sequence.
Cf. A018252.
Sequence in context: A202268 A084985 A068631 * A163520 A273546 A176539
KEYWORD
nonn,look
AUTHOR
Rémy Sigrist, Jan 31 2021
STATUS
approved