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 A169812 #9 Jul 08 2019 12:29:55 %S A169812 0,0,1,7,7,2,5,12,10,14,9,10,15,10,11,21,19,20,17,18,17,18,21,16,26, %T A169812 30,31,26,31,22,29,38,37,38,39,45,39,34,35,32,43,34,41,42,43,42,45,58, %U A169812 50,52,55,50,55,62,51,48,61,62,57,48,63,58,57,71,69,74,65,66,65,78,69,68,75,78 %N A169812 a(n) = n XOR d(n) (cf. A000005). %H A169812 Amiram Eldar, <a href="/A169812/b169812.txt">Table of n, a(n) for n = 1..10000</a> %t A169812 a[n_] := BitXor[n, DivisorSigma[0, n]]; Array[a, 100] (* _Amiram Eldar_, Jul 08 2019 *) %o A169812 (PARI) a(n)=bitxor(n, numdiv(n)); \\ _Michel Marcus_, Jul 08 2019 %Y A169812 Cf. A000005, A070883, A169810, A169811, A169813, A169814. %K A169812 nonn %O A169812 1,4 %A A169812 _N. J. A. Sloane_, May 28 2010