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A087842
a(n) = a(a(a(n - a(n-1)))) + a(n - a(n-2)).
3
1, 1, 2, 3, 3, 3, 4, 4, 4, 4, 6, 5, 6, 6, 6, 6, 8, 7, 8, 8, 8, 8, 8, 8, 11, 9, 9, 11, 11, 11, 11, 11, 11, 11, 11, 14, 12, 11, 12, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 17, 15, 14, 14, 17, 17, 15, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 21, 18, 17, 17, 21, 20, 17, 21, 21, 21, 18, 21
OFFSET
1,3
COMMENTS
A fourth-order recursive version of Hofstadter Q of the first term of A005185.
LINKS
MATHEMATICA
digits=200 Hofstadter[n_Integer?Positive] := Hofstadter[n] = Hofstadter[Hofstadter[Hofstadter[n - Hofstadter[n-1]]]] + Hofstadter[n - Hofstadter[n-2]] Hofstadter[1] = Hofstadter[2] = 1 a1=Table[Hofstadter[n], {n, 1, digits}]
CROSSREFS
Cf. A005185.
Sequence in context: A057627 A013940 A029129 * A201206 A101776 A189721
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Oct 07 2003
STATUS
approved