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 A217558 #14 May 02 2024 10:17:39
%S A217558 0,16,32,48,64,80,96,112,128,144,160,176,192,208,224,240,1,17,33,49,
%T A217558 65,81,97,113,129,145,161,177,193,209,225,241,2,18,34,50,66,82,98,114,
%U A217558 130,146,162,178,194,210,226,242,3,19,35,51,67,83,99,115,131,147,163,179,195,211,227,243
%N A217558 Split-and-swap on 8-bit integers.
%C A217558 Split-and-swap consists of spliting a binary word into two halves and swapping the parts over to form a new word, for example 11001010 becomes 10101100.
%C A217558 There are 256 terms to the sequence. - _Harvey P. Dale_, Jul 14 2015
%C A217558 Fixed points are the multiples of 17 (A008599) in {0..255}. - _Alois P. Heinz_, May 02 2024
%H A217558 Harvey P. Dale, <a href="/A217558/b217558.txt">Table of n, a(n) for n = 0..255</a>
%e A217558 a(17)=17 because 17 is 00010001 which is invariant over the SaS rule.
%e A217558 a(19)=49 because 00010011 becomes 00110001.
%t A217558 FromDigits[#,2]&/@(Join[Take[#,-4],Take[#,4]]&/@Select[Tuples[{0,1},8], Length[#] ==8 &]) (* _Harvey P. Dale_, Jul 14 2015 *)
%o A217558 (JavaScript)
%o A217558 for (i=0;i<16;i++)
%o A217558 for (j=0;j<16;j++)
%o A217558 document.write(j*16+i+", ");
%o A217558 (PARI) A217558(n)=[1,16]*divrem(n,16) \\ - _M. F. Hasler_, Oct 07 2012
%Y A217558 Cf. A008599.
%K A217558 nonn,fini,full,base
%O A217558 0,2
%A A217558 _Jon Perry_, Oct 06 2012