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.

A186222 Adjusted joint rank sequence of (g(i)) and (f(j)) with f(i) after g(j) when f(i)=g(j), where f and g are the triangular numbers and squares. Complement of A186221.

Original entry on oeis.org

1, 4, 6, 9, 11, 13, 16, 18, 21, 23, 26, 28, 30, 33, 35, 38, 40, 42, 45, 47, 50, 52, 55, 57, 59, 62, 64, 67, 69, 71, 74, 76, 79, 81, 83, 86, 88, 91, 93, 96, 98, 100, 103, 105, 108, 110, 112, 115, 117, 120, 122, 125, 127, 129, 132, 134, 137, 139, 141, 144, 146, 149, 151, 154, 156, 158, 161, 163, 166, 168, 170, 173, 175, 178, 180, 182, 185, 187, 190, 192, 195, 197, 199, 202, 204, 207, 209, 211, 214, 216, 219, 221, 224, 226, 228, 231, 233, 236, 238, 240
Offset: 1

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Author

Clark Kimberling, Feb 15 2011

Keywords

Comments

See A186221.

Examples

			See A186221.
		

Crossrefs

Programs

  • Magma
    [n + Floor(-1/2 + Sqrt(2*n^2)): n in [1..120]]; // G. C. Greubel, Aug 18 2018
  • Mathematica
    (* adjusted joint ranking; general formula *)
    d=-1/4; u=1/2; v=1/2; w=0; x=1; y=0; 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}] (* A186221 *)
    Table[b[n],{n,1,100}] (* A186222 *)
    Table[n + Floor[Sqrt[2*n^2] - 1/2], {n, 1, 120}] (* G. C. Greubel, Aug 18 2018 *)
  • PARI
    vector(120, n, n + floor(-1/2 + sqrt(2*n^2))) \\ G. C. Greubel, Aug 18 2018
    

Formula

a(n) = n + floor(-1/2 + sqrt(2*n^2)).