A087842 - OEIS

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A087842

a[n] =a[a[a[n - a[n-1]]]] + a[n - a[n-2]]

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 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`A fourth-order recursive version of Hofstadter Q of the first term of A005185.`
	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` `Adjacent sequences: A087839 A087840 A087841 * A087843 A087844 A087845`
	KEYWORD	`nonn`
	AUTHOR	`Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Oct 07 2003`

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Last modified February 17 02:08 EST 2012. Contains 205978 sequences.