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A006158 a(n) = a(a(n-3)) + a(n-a(n-3)).
(Formerly M0447)
4
1, 1, 1, 2, 3, 4, 4, 4, 5, 6, 6, 7, 8, 8, 8, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 16, 16, 16, 16, 16, 16, 16, 17, 18, 18, 19, 20, 21, 21, 22, 23, 24, 25, 25, 26, 27, 28, 29, 29, 29, 29, 29, 30, 31, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 33, 34, 34, 35, 36, 37, 37, 38, 39, 40, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

J. Arkin, D. C. Arney, L. S. Dewald and W. E. Ebel, Jr., Families of recursive sequences, J. Rec. Math., 22 (No. 22, 1990), 85-94.

B. W. Conolly, ``Meta-Fibonacci sequences,'' in S. Vajda, editor, Fibonacci and Lucas Numbers and the Golden Section. Halstead Press, NY, 1989, pp. 127-138.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Iain Fox, Table of n, a(n) for n = 1..10000

I. Vardi, Email to N. J. A. Sloane, Jun. 1991

MAPLE

a := proc(n) option remember: if 1 <= n and n <=3 then RETURN(1) fi: a(a(n-3)) +a(n-a(n-3)) end: for n from 1 to 100 do printf(`%d, `, a(n)) od:

PROG

(PARI) first(n) = my(res = vector(n, i, 1)); for(x=4, n, res[x]=res[res[x-3]] + res[x-res[x-3]]); res \\ Iain Fox, Oct 24 2018

CROSSREFS

Sequence in context: A173073 A073425 A087876 * A340203 A135414 A326821

Adjacent sequences:  A006155 A006156 A006157 * A006159 A006160 A006161

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from James A. Sellers, Apr 20 2001

STATUS

approved

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Last modified June 14 12:04 EDT 2021. Contains 345025 sequences. (Running on oeis4.)