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A186315
Adjusted joint rank sequence of (f(i)) and (g(j)) with f(i) before g(j) when f(i)=g(j), where f and g are the squares and hexagonal numbers. Complement of A186316.
4
1, 3, 5, 7, 8, 10, 12, 13, 15, 17, 19, 20, 22, 24, 25, 27, 29, 30, 32, 34, 36, 37, 39, 41, 42, 44, 46, 48, 49, 51, 53, 54, 56, 58, 59, 61, 63, 65, 66, 68, 70, 71, 73, 75, 77, 78, 80, 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
OFFSET
1,2
COMMENTS
See A186219 for a discussion of adjusted joint rank sequences.
EXAMPLE
First, write
1..4...9...16..25....36....49. (squares)
1....6...15.......28....45.... (hexagonal)
Replace each number by its rank, where ties are settled by ranking the square number before the hexagonal:
a=(1,3,5,7,8,10,12,13,...)=A186315.
b=(2,4,6,9,11,14,16,18,...)=A186316.
MATHEMATICA
(* adjusted joint ranking; general formula *)
d=1/2; u=1; v=0; w=0; x=2; y=-1; z=0;
h[n_]:=-y+(4x(u*n^2+v*n+w-z-d)+y^2)^(1/2);
a[n_]:=n+Floor[h[n]/(2x)];
k[n_]:=-v+(4u(x*n^2+y*n+z-w+d)+v^2)^(1/2);
b[n_]:=n+Floor[k[n]/(2u)];
Table[a[n], {n, 1, 100}] (* A186315 *)
Table[b[n], {n, 1, 100}] (* A186316 *)
CROSSREFS
A000290 (squares), A000384 (hexagonal numbers).
Sequence in context: A288467 A276224 A186342 * A285074 A186219 A185050
KEYWORD
nonn
AUTHOR
Clark Kimberling, Feb 17 2011
STATUS
approved