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 A178731 #11 Sep 08 2022 08:45:54 %S A178731 0,4,8,12,16,28,24,36,32,36,56,60,48,76,72,68,64,68,72,76,112,124,120, %T A178731 100,96,100,152,156,144,140,136,132,128,132,136,140,144,156,152,228, %U A178731 224,228,248,252,240,204,200,196,192,196,200,204,304,316,312,292,288,292 %N A178731 a(n) = n XOR 5n, where XOR is bitwise XOR. %H A178731 Vincenzo Librandi, <a href="/A178731/b178731.txt">Table of n, a(n) for n = 0..5000</a> %t A178731 f[n_] := BitXor[n, 5 n]; Array[f, 60, 0] (* _Robert G. Wilson v_, Jun 09 2010 *) %o A178731 (Magma) [BitwiseXor(n, 5*n): n in [0..70]]; // _Vincenzo Librandi_, Jul 11 2017 %o A178731 (PARI) a(n) = bitxor(n, 5*n); \\ _Michel Marcus_, Jul 11 2017 %Y A178731 Cf. A048724, A178729, A048725, A178732, A178733, A178734, A178735, A178736. - _Robert G. Wilson v_, Jun 09 2010 %K A178731 nonn %O A178731 0,2 %A A178731 _Dmitry Kamenetsky_, Jun 08 2010 %E A178731 a(30) onwards from _Robert G. Wilson v_, Jun 09 2010