cp's OEIS Frontend

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.

A186328 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 pentagonal numbers and the hexagonal numbers. Complement of A186329.

Original entry on oeis.org

1, 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

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Author

Clark Kimberling, Feb 17 2011

Keywords

Comments

See A186219 for a discussion of adjusted joint rank sequences.

Examples

			First, write
1..5...12....22.....35......  (pentagonal)
1....6....15....28.......45.. (hexagonal)
Then replace each number by its rank, where ties are settled by ranking the pentagonal number before the hexagonal:
a=(1,3,5,7,9,11,13,15,16,....)=A186328
b=(2,4,6,8,10,12,14,17,19,...)=A186329.
		

Crossrefs

A000384 (pentagonal), A000384 (hexagonal).

Programs

  • 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}]  (* A186328 *)
    Table[b[n], {n, 1, 100}]  (* A186329 *)