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A330004
a(1) = 0, and for n > 0, a(n+1) = u - v where u (resp. v) is the number of terms equal to a(n) (resp. a(n)+1) among the first n terms.
3
0, 1, 1, 2, 1, 2, 2, 3, 1, 1, 2, 3, 2, 3, 3, 4, 1, 1, 2, 2, 3, 4, 2, 3, 4, 3, 4, 4, 5, 1, 0, -6, 1, 1, 2, 2, 3, 3, 4, 5, 2, 2, 3, 4, 5, 3, 4, 5, 4, 5, 5, 6, 1, -1, -1, 0, -8, 1, 0, -8, 2, 2, 3, 3, 4, 4, 5, 6, 2, 2, 3, 3, 4, 5, 6, 3, 4, 5, 6, 4, 5, 6, 5, 6, 6
OFFSET
1,4
The sequence has chaotic features (see plot in Links section).
EXAMPLE
The first terms, alongside u and v, are:
n a(n) u v
-- ---- - -
1 0 1 0
2 1 1 0
3 1 2 0
4 2 1 0
5 1 3 1
6 2 2 0
7 2 3 0
8 3 1 0
9 1 4 3
10 1 5 3
PROG
(PARI) for (n=1, #(a=vector(85)), print1 (a[n]=if (n==1, 0, sum(k=1, n-1, (a[k]==a[n-1])-(a[k]==a[n-1]+1)))", "))
CROSSREFS
See A329981 for similar sequences.
Sequence in context: A037194 A326130 A205510 * A332901 A292583 A330372
KEYWORD
sign,look
AUTHOR
Rémy Sigrist, Nov 26 2019
STATUS
approved

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Last modified September 20 16:06 EDT 2024. Contains 376074 sequences. (Running on oeis4.)