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A308172 a(0)=1; thereafter a(n) = smallest number missing from A081145 after A081145(n) has been calculated. 2
1, 2, 3, 3, 3, 5, 5, 5, 6, 6, 6, 9, 9, 9, 10, 10, 10, 11, 11, 11, 13, 13, 13, 15, 15, 15, 17, 17, 17, 18, 18, 18, 19, 19, 19, 22, 22, 22, 23, 23, 24, 24, 24, 26, 26, 26, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 32, 35, 35, 35, 36, 36, 36, 38, 38, 38, 39, 39, 39, 40, 40, 43 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
More than the usual number of terms are shown in order to emphasize the irregularities.
Usually the terms appear in groups of three, but there are many irregularities. To see them, take this sequence, apply the RUNS transform twice, and bisect the result. This produces a very irregular sequence, 12, 10, 1, 46, 2, 2, 3, 2, 5, 6, 7, 10, 9, 13, 25, 5, 24, 1, 42, ... It would be nice to understand this better.
LINKS
EXAMPLE
n=4: Terms 1 through 4 of A081145 are 1,2,4,7. After A081145(4)=7 has been calculated, the numbers not yet in A081145 are 3,5,6,8,..., so a(4) = 3.
PROG
(PARI) See Links section.
CROSSREFS
Cf. A081145.
Sequence in context: A097224 A087418 A087731 * A227559 A234968 A141784
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 16 2019
STATUS
approved

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Last modified June 6 19:21 EDT 2024. Contains 373134 sequences. (Running on oeis4.)