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A357943 a(0) = 0; a(1) = 1, a(2) = 2; for n > 2, a(n) is the number of times the term a(n - 1 - a(n-1)) has appeared in the sequence. 2
0, 1, 2, 1, 1, 3, 1, 1, 5, 5, 5, 1, 3, 3, 3, 6, 3, 5, 5, 5, 5, 1, 7, 1, 1, 9, 5, 9, 8, 8, 9, 9, 1, 4, 2, 10, 4, 10, 4, 2, 2, 3, 3, 4, 4, 4, 7, 4, 7, 7, 7, 7, 7, 7, 8, 8, 7, 9, 9, 9, 9, 9, 9, 9, 4, 11, 4, 11, 9, 12, 12, 12, 12, 12, 12, 12, 12, 9, 13, 2, 13, 2, 6, 8, 8, 8, 13, 8, 6, 3, 3, 8, 9, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
In the first 100 million terms the longest run of consecutive equal terms is eight : a(69)..a(76) = 12. There is no other run of equal length in this range, and it is unknown if a longer run exists.
Other than the initial three terms, the first time a term exists that is one more than the previous term is a(29) = 8, a(30) = 9. Remarkably the first time two such consecutive terms exists is not until a(60917874) = 5394, a(60917875) = 5395, a(60917876) = 5396. It is unknown if three or more such terms exist.
Note that if the sequence starts with just a(0) = 0, a(1) = 1 then the resulting sequence is A003056.
The sequence is conjectured to contain all positive numbers. See A357944 for the index of where a given number first appears.
LINKS
Scott R. Shannon, Frequency distribution of the first 10000000 terms. The maximum x value is 4858, which is the number of times 20 has appeared.
EXAMPLE
a(5) = 3 as the term at a(4 - a(4)) = a(4 - 1) = a(3) = 1, and 1 has appeared three times in the sequence.
MATHEMATICA
nn = 83; c[_] = 0; Array[Set[{a[#], c[#]}, {#, 1}] &, 3, 0]; Do[(a[n] = c[#]; c[c[#]]++) &[a[n - a[n - 1] - 1]], {n, 3, nn}]; Array[a, nn, 0] (* Michael De Vlieger, Oct 23 2022 *)
CROSSREFS
Sequence in context: A280698 A217667 A240850 * A194086 A342723 A164659
KEYWORD
nonn,look
AUTHOR
Scott R. Shannon, Oct 22 2022
STATUS
approved

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Last modified May 13 07:22 EDT 2024. Contains 372498 sequences. (Running on oeis4.)