This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A035337 #62 Mar 28 2025 10:24:06 %S A035337 3,11,16,24,32,37,45,50,58,66,71,79,87,92,100,105,113,121,126,134,139, %T A035337 147,155,160,168,176,181,189,194,202,210,215,223,231,236,244,249,257, %U A035337 265,270,278,283,291,299,304,312 %N A035337 Third column of Wythoff array. %C A035337 Also, positions of 3's in A139764, the smallest term in Zeckendorf representation of n. - _John W. Layman_, Aug 25 2011 %C A035337 The formula a(n) = 3*A003622(n)-n+1 = 3AA(n)-n+1 conjectured by Layman below is correct, since it is well known that AA(n)+1 = B(n) = A(n)+n, where B = A001950, and so 3AA(n)-n+1 = 3B(n)-n-2 = 3A(n)+2n-2. - _Michel Dekking_, Aug 31 2017 %C A035337 From _Amiram Eldar_, Mar 21 2022: (Start) %C A035337 Numbers k for which the Zeckendorf representation A014417(k) ends with 1, 0, 0. %C A035337 The asymptotic density of this sequence is 1/phi^4 = 2/(7+3*sqrt(5)), where phi is the golden ratio (A001622). (End) %H A035337 Amiram Eldar, <a href="/A035337/b035337.txt">Table of n, a(n) for n = 0..10000</a> %H A035337 Jon Asier Bárcena-Petisco, Luis Martínez, María Merino, Juan Manuel Montoya, and Antonio Vera-López, <a href="https://arxiv.org/abs/2503.19696">Fibonacci-like partitions and their associated piecewise-defined permutations</a>, arXiv:2503.19696 [math.CO], 2025. See p. 4. %H A035337 J. H. Conway and N. J. A. Sloane, <a href="/A019586/a019586.pdf">Notes on the Para-Fibonacci and related sequences</a>. %H A035337 Clark Kimberling, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL11/Kimberling/kimberling719a.html">Complementary equations and Wythoff Sequences</a>, JIS, Vol. 11 (2008), Article 08.3.3. %H A035337 N. J. A. Sloane, <a href="/classic.html#WYTH">Classic Sequences</a>. %F A035337 a(n) = F(4)A(n)+F(3)(n-1) = 3A(n)+2n-2, where A = A000201 and F = A000045. - _Michel Dekking_, Aug 31 2017 %F A035337 It appears that a(n) = 3*A003622(n) - n + 1. - _John W. Layman_, Aug 25 2011 %p A035337 t := (1+sqrt(5))/2 ; [ seq(3*floor((n+1)*t)+2*n,n=0..80) ]; %t A035337 Table[3 Floor[n GoldenRatio] + 2 n - 2, {n, 46}] (* _Michael De Vlieger_, Aug 31 2017 *) %o A035337 (Python) %o A035337 from sympy import floor %o A035337 from mpmath import phi %o A035337 def a(n): return 3*floor((n + 1)*phi) + 2*n # _Indranil Ghosh_, Jun 10 2017 %o A035337 (Python) %o A035337 from math import isqrt %o A035337 def A035337(n): return 3*(n+isqrt(5*n**2)>>1)+(n-1<<1) # _Chai Wah Wu_, Aug 11 2022 %o A035337 (PARI) a(n) = 2*n + 3*floor((1+sqrt(5))*(n+1)/2); \\ _Altug Alkan_, Sep 18 2017 %Y A035337 Cf. A001622, A014417, A139764. %Y A035337 Let A = A000201, B = A001950. Then AA = A003622, AB = A003623, BA = A035336, BB = A101864. The eight triples AAA, AAB, ..., BBB are A134859, A134860, A035337, A134862, A134861, A134863, A035338, A134864, resp. %K A035337 nonn %O A035337 0,1 %A A035337 _N. J. A. Sloane_ and _J. H. Conway_