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 A292256 #10 Sep 30 2017 16:06:43 %S A292256 0,0,0,0,0,0,0,1,0,0,0,0,0,0,2,3,0,0,0,1,0,0,0,0,0,0,0,0,4,4,6,6,0,0, %T A292256 0,0,0,0,2,3,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,8,8,8,9,12,12,12,12,0,0, %U A292256 0,1,0,0,0,0,0,0,0,0,4,4,6,6,0,0,0,0,0,0,2,3,0,0,0,1,0,0,0,0,0,0,0,0,0,0,2,2,0,0,0,0,0,0,2,2,16,16,16,16,16,16 %N A292256 a(n) = A292255(A163511(n)). %C A292256 Because A292255(n) = a(A243071(n)), the sequence works as a "masking function" where the 1-bits in a(n) (always a subset of the 1-bits in binary expansion of n) indicate the numbers that are either of the form 12k+5 or of the form 12k+7 in binary tree A163511 (or its mirror image tree A005940) on that trajectory which leads from the root of the tree to the node containing A163511(n). %C A292256 The AND - XOR formulas just restate the fact that J(3|n) = J(-1|n)*J(-3|n), as the Jacobi-symbol is multiplicative (also) with respect to its upper argument. %H A292256 Antti Karttunen, <a href="/A292256/b292256.txt">Table of n, a(n) for n = 0..8191</a> %H A292256 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A292256 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %F A292256 a(n) = A292255(A163511(n)). %F A292256 a(n) = A292264(n) AND (A292274(n) XOR A292946(n)), where AND is bitwise-and (A004198) and XOR is bitwise-XOR (A003987). %F A292256 a(n) = A292264(n) AND (A292271(n) XOR A292942(n)). [See comments]. %F A292256 For all n >= 0, a(n) + A292944(n) + A292254(n) = n. %o A292256 (Scheme) (define (A292256 n) (A292255 (A163511 n))) %Y A292256 Cf. A005940, A163511, A292255. %Y A292256 Cf. also A292247, A292248, A292254, A292264, A292271, A292274, A292592, A292593, A292942, A292944, A292946 (for similarly constructed sequences). %K A292256 nonn %O A292256 0,15 %A A292256 _Antti Karttunen_, Sep 28 2017