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 A169813 #11 Nov 26 2017 07:14:55 %S A169813 0,1,7,3,3,10,15,7,4,24,7,16,3,22,23,15,3,53,7,62,53,50,15,36,6,48,51, %T A169813 36,3,86,63,31,17,20,19,127,3,26,31,114,3,74,7,120,99,102,31,76,8,111, %U A169813 123,86,3,78,127,64,105,96,7,148,3,94,87,63,21,210,7,58,37,214,15,139,3,56 %N A169813 a(n) = n XOR sigma(n), where sigma(n) is the number of divisors of n, A000203. %H A169813 Antti Karttunen, <a href="/A169813/b169813.txt">Table of n, a(n) for n = 1..16384</a> %H A169813 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A169813 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %o A169813 (Scheme) (define (A169813 n) (A003987bi n (A000203 n))) ;; Where A003987bi implements the bitwise-XOR, A003987 and code for A000203 can be found under that entry. - _Antti Karttunen_, Nov 25 2017 %o A169813 (PARI) a(n) = bitxor(n, sigma(n)); \\ _Michel Marcus_, Nov 25 2017 %Y A169813 Cf. A000203, A003987, A070883, A169810, A169811, A169812, A169814. %Y A169813 Cf. also A106409, A178910, A227320, A294899. %K A169813 nonn,look %O A169813 1,3 %A A169813 _N. J. A. Sloane_, May 28 2010