A186330 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 pentagonal numbers and the hexagonal numbers. Complement of A186331.
2, 3, 5, 7, 9, 11, 13, 15, 16, 18, 20, 22, 24, 26, 28, 29, 31, 33, 35, 37, 39, 41, 43, 44, 46, 48, 50, 52, 54, 56, 57, 59, 61, 63, 65, 67, 69, 71, 72, 74, 76, 78, 80, 82, 84, 85, 87, 89, 91, 93, 95, 97, 99, 100, 102, 104, 106, 108, 110, 112, 113, 115, 117, 119, 121, 123, 125, 126, 128, 130, 132, 134, 136, 138, 140, 141, 143, 145, 147, 149, 151, 153, 154, 156, 158, 160, 162, 164, 166, 168, 169, 171, 173, 175, 177, 179, 181, 182, 184, 186
Offset: 1
Keywords
Examples
First, write 1..5...12....22.....35...... (pentagonal) 1....6....15....28.......45.. (hexagonal) Replace each number by its rank, where ties are settled by ranking the pentagonl number after the hexagonal: a=(1,3,5,7,9,11,13,15,16,....)=A186330 b=(2,4,6,8,10,12,14,17,19,...)=A186331.
Programs
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Mathematica
(* adjusted joint ranking; general formula *) d=-1/2; u=3/2; v=-1/2; 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}] (* A186330 *) Table[b[n], {n, 1, 100}] (* A186331 *)
Comments