This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A265385 Sequence defined by a(1)=a(2)=1 and a(n) = gray(a(n-1) + a(n-2)), with gray(m) = A003188(m). 3
 1, 1, 3, 6, 13, 26, 52, 105, 211, 418, 847, 1673, 3380, 6755, 13404, 27104, 53538, 108163, 216183, 428935, 867329, 1713228, 3461227, 6917868, 13725948, 27754524, 54823316, 110759272, 221371778, 439230367, 888144817, 1754346232, 3544296957, 7083888783 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS This recurrence is reminiscent of Fibonacci's, except that the result of each step is passed through the binary-reflected Gray code mapping, which introduces a degree of pseudo-randomness. Conjecture: The mean growth rate r(n) = (a(2n)/a(n))^(1/n) appears to converge exactly to 2, with the consecutive-terms ratio s(n) = a(n)/a(n-1) exhibiting relatively small (~1%) but persistent fluctuations around the mean value. This contrasts what one might first expect, that sequence's growth rate were similar to that of the Fibonacci sequence, i.e., the golden ratio, since gray(m) just permutes every block of numbers ranging from 2^k to 2^l-1, for any 0>1); a=vector(1000); a[1]=1; a[2]=1; for(n=3, #a, a[n]=gray(a[n-1]+a[n-2])); a CROSSREFS Cf. A000045, A003188, A265386, A265387. Sequence in context: A079941 A255125 A267367 * A019300 A072762 A081254 Adjacent sequences:  A265382 A265383 A265384 * A265386 A265387 A265388 KEYWORD nonn AUTHOR Stanislav Sykora, Dec 07 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 20 05:51 EDT 2019. Contains 327212 sequences. (Running on oeis4.)