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A070868 a(1) = a(2) = 1; a(n) = a(a(n-1)) + a(n+1 - 2*a(n-1)). 2
1, 1, 2, 2, 2, 3, 3, 4, 3, 4, 4, 4, 5, 4, 6, 5, 6, 6, 7, 6, 7, 6, 7, 7, 7, 8, 8, 9, 7, 9, 7, 10, 8, 11, 8, 11, 9, 10, 10, 11, 10, 11, 10, 11, 11, 11, 12, 11, 13, 12, 13, 13, 14, 12, 14, 11, 15, 13, 16, 12, 14, 12, 15, 14, 14, 14, 15, 16, 15, 16, 16, 15, 17, 16, 16, 16, 16, 17, 17, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 129.

LINKS

Table of n, a(n) for n=1..80.

Nick Hobson, Python program for this sequence

Eric Weisstein's World of Mathematics, Wolfram Sequences

Index entries for Hofstadter-type sequences

MATHEMATICA

a[1] = a[2] = 1; a[n_] := a[n] = a[ a[n - 1]] + a[n + 1 - 2*a[n - 1]]; Table[ a[n], {n, 1, 80}]

CROSSREFS

Sequence in context: A177903 A107325 A003050 * A342219 A272612 A155216

Adjacent sequences:  A070865 A070866 A070867 * A070869 A070870 A070871

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 19 2002

EXTENSIONS

More terms from Robert G. Wilson v, May 20 2002

STATUS

approved

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Last modified August 5 01:51 EDT 2021. Contains 346456 sequences. (Running on oeis4.)