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A257862
a(n) = n if n <= 3, otherwise a(n) is the smallest number not already used and relatively prime to a(n-1) such that the set of prime divisors of one of the numbers {a(n-2), a(n)} is a subset of the set of prime divisors of the other.
1
1, 2, 3, 4, 9, 8, 15, 14, 5, 7, 10, 21, 16, 27, 20, 33, 25, 11, 30, 77, 6, 49, 12, 35, 18, 125, 24, 55, 32, 121, 26, 99, 13, 66, 65, 22, 169, 44, 39, 64, 81, 28, 45, 56, 75, 98, 135, 112, 165, 128, 225, 34, 105, 17, 63, 68, 147, 136, 189, 170, 231, 40, 243, 50
OFFSET
1,2
COMMENTS
The sequence is an analog of the Yellowstone sequence A098550 with a more stringent condition on neighboriong terms at distance 2. However, we conjecture that, as with A098550, this is a permutation of the positive integers.
By definition, every pair of neighboring terms at distance 2 are strictly connected numbers as defined in comment in A257112.
LINKS
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, May 11 2015
EXTENSIONS
More terms from Peter J. C. Moses, May 11 2015
STATUS
approved