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 A186317 #4 Mar 30 2012 18:57:18 %S A186317 2,3,5,7,8,10,12,13,15,17,19,20,22,24,25,27,29,30,32,34,36,37,39,41, %T A186317 42,44,46,48,49,51,53,54,56,58,60,61,63,65,66,68,70,71,73,75,77,78,80, %U A186317 82,83,85,87,89,90,92,94,95,97,99,100,102,104,106,107,109,111,112,114,116,118,119,121,123,124,126,128,129,131,133,135,136,138,140,141,143,145,147,148,150,152,153,155,157,159,160,162,164,165,167,169,170 %N A186317 Adjusted joint rank sequence of (f(i)) and (g(j)) with f(i) after g(j) when f(i)=g(j), where f and g are the squares and hexagonal numbers. Complement of A186318. %e A186317 First, write %e A186317 1..4...9...16..25....36....49. (squares) %e A186317 1....6...15.......28....45.... (hexagonals) %e A186317 Replace each number by its rank, where ties are settled by ranking the square number after the hexagonal: %e A186317 a=(2,3,5,7,8,10,12,13,...)=A186317. %e A186317 b=(1,4,6,9,11,14,16,18,...)=A186318. %t A186317 (* adjusted joint ranking; general formula *) %t A186317 d=-1/2; u=1; v=0; w=0; x=2; y=-1; z=0; %t A186317 h[n_]:=-y+(4x(u*n^2+v*n+w-z-d)+y^2)^(1/2); %t A186317 a[n_]:=n+Floor[h[n]/(2x)]; %t A186317 k[n_]:=-v+(4u(x*n^2+y*n+z-w+d)+v^2)^(1/2); %t A186317 b[n_]:=n+Floor[k[n]/(2u)]; %t A186317 Table[a[n], {n, 1, 100}] (* A186317 *) %t A186317 Table[b[n], {n, 1, 100}] (* A186318 *) %Y A186317 Cf. A186315, A186316, A186318. %K A186317 nonn %O A186317 1,1 %A A186317 _Clark Kimberling_, Feb 17 2011