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 A026250 #15 Feb 16 2025 08:32:35 %S A026250 3,6,1,10,13,2,17,20,23,4,27,30,5,34,37,40,7,44,47,8,51,54,9,58,61,64, %T A026250 11,68,71,12,75,78,81,14,85,88,15,92,95,16,99,102,105,18,109,112,19, %U A026250 116,119,122,21,126,129,22,133,136,139,24,143,146 %N A026250 Beginning with the natural numbers, swap [ k*sqrt(2) ] and [ k*(2 + sqrt(2)) ], for all k >= 1. %C A026250 Self-inverse integer permutation induced by Beatty sequences for sqrt(2) and 2+sqrt(2). - _Reinhard Zumkeller_, Jun 11 2005 %H A026250 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BeattySequence.html">Beatty Sequence</a> %H A026250 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %H A026250 <a href="/index/Be#Beatty">Index entries for sequences related to Beatty sequences</a> %F A026250 a(A001951(n)) = A001952(n) and a(A001952(n)) = A001951(n). - _Reinhard Zumkeller_, Jun 11 2005 %Y A026250 Cf. A026255, A026262. %K A026250 nonn %O A026250 1,1 %A A026250 _Clark Kimberling_