A186290 - OEIS

%I #4 Mar 30 2012 18:57:18

%S 2,3,5,7,9,11,12,14,16,18,20,21,23,25,27,29,31,32,34,36,38,40,41,43,

%T 45,47,49,51,52,54,56,58,60,61,63,65,67,69,71,72,74,76,78,80,81,83,85,

%U 87,89,90,92,94,96,98,100,101,103,105,107,109,110,112,114,116,118,120,121,123,125,127,129,130,132,134,136,138,140,141,143,145,147,149,150,152,154,156,158,160,161,163,165,167,169,170,172,174,176,178,180,181

%N 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 pentagonal numbers.  Complement of A186291.

%C See A186219 for a discussion of adjusted joint rank sequences.

%e First, write

%e 1..4...9....16....25..36..49..... (squares

%e 1....5...12....22....35......51.. (pentagonal)

%e Replace each number by its rank, where ties are settled by ranking the square number after the pentagonal:

%e a=(2,3,5,7,9,11,12,14,....)=A186290.

%e b=(1,4,6,8,10,13,15,17,...)=A186291.

%t (* adjusted joint ranking; general formula *)

%t d=-1/2; u=1; v=0; w=0; x=3/2; y=-1/2; z=0;

%t h[n_]:=-y+(4x(u*n^2+v*n+w-z-d)+y^2)^(1/2);

%t a[n_]:=n+Floor[h[n]/(2x)];

%t k[n_]:=-v+(4u(x*n^2+y*n+z-w+d)+v^2)^(1/2);

%t b[n_]:=n+Floor[k[n]/(2u)];

%t Table[a[n], {n, 1, 100}]  (* A186290 *)

%t Table[b[n], {n, 1, 100}]  (* A186291 *)

%K nonn

%O 1,1

%A _Clark Kimberling_, Feb 17 2011