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A331631
Let S = smallest missing positive number, adjoin S, 3*S, 9*S, 27*S, 81*S, ... to the sequence until reaching a term that has S as a substring; reset S to the smallest missing positive number, repeat.
1
1, 3, 9, 27, 81, 2, 6, 18, 54, 162, 4, 12, 36, 108, 324, 5, 15, 7, 21, 63, 189, 567, 8, 24, 72, 216, 648, 10, 30, 90, 270, 810, 11, 33, 99, 297, 891, 2673, 8019, 24057, 72171, 216513, 649539, 1948617, 5845851, 17537553, 52612659, 157837977, 473513931, 1420541793, 4261625379, 12784876137, 38354628411, 13, 39
OFFSET
1,2
COMMENTS
This is conjectured to be a permutation of the positive integers (see the Crossrefs section).
LINKS
EXAMPLE
The process begins like this:
Initially S = 1 is the smallest missing number, so we have:
S = 1, 3, 9, 27, 81, stop (because 81 contains S), S = 2, 6, 18, 54, 162, stop, S = 4, 12, 36, 108, 324, stop, S = 5, 15, stop, S = 7, 21, 63, 189, 567, ...
CROSSREFS
Cf. A331440 (where one adjoins 2*S, 4*S, 8*S, 16*S, ... to the sequence).
Sequence in context: A289781 A209239 A318773 * A036142 A036160 A271352
KEYWORD
base,nonn
AUTHOR
Eric Angelini and Carole Dubois, Jan 23 2020
STATUS
approved