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 A063510 a(1) = 1, a(n) = a(floor(square root(n)) + 1 for n > 1. 2
 1, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = A010096(n) until n = 255, but 5 = a(256) <> A010096(256) = 4. The least k such that a(k)=n for n >= 2 is given by k = 2^(2^(n-2)) so the closed form for a(n) follows. - Benoit Cloitre, Apr 28 2005 LINKS FORMULA a(1)=1; for n >= 2, a(n) = floor(log(4*log(n)/log(2))/log(2)). - Benoit Cloitre, Apr 28 2005 Equivalently, a(n) = 2 + floor(log_2(log_2(n))) for n > 1. - Charles R Greathouse IV, Dec 19 2011 PROG (PARI) a(n)=if(n<2, 1, floor(log(4*log(n)/log(2))/log(2))) (Haskell) a063510 1 = 1 a063510 n = a063510 (a000196 n) + 1 -- Reinhard Zumkeller, Mar 16 2012 CROSSREFS Cf. A010096. Cf. A000196. Sequence in context: A157639 A010096 A230864 * A156878 A214454 A140474 Adjacent sequences:  A063507 A063508 A063509 * A063511 A063512 A063513 KEYWORD easy,nonn AUTHOR Reinhard Zumkeller, Jul 30 2001 STATUS approved

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Last modified April 1 10:33 EDT 2020. Contains 333159 sequences. (Running on oeis4.)