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.

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.

Original entry on oeis.org

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

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Author

Clark Kimberling, Feb 17 2011

Keywords

Comments

Does this differ (apart from a(1)) from A186329 or A186328? - R. J. Mathar, Feb 25 2011

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.
		

Crossrefs

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}]  (* A186330 *)
    Table[b[n], {n, 1, 100}]  (* A186331 *)