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.

A256797 Nonpositive part of the minimal alternating squares representation of n.

Original entry on oeis.org

0, 2, 1, 0, 4, 4, 4, 1, 0, 10, 9, 4, 4, 4, 1, 0, 9, 11, 10, 9, 4, 4, 4, 1, 0, 20, 9, 9, 11, 10, 9, 4, 4, 4, 1, 0, 16, 20, 20, 9, 9, 11, 10, 9, 4, 4, 4, 1, 0, 18, 17, 16, 20, 20, 9, 9, 11, 10, 9, 4, 4, 4, 1, 0, 16, 16, 18, 17, 16, 20, 20, 9, 9, 11, 10, 9, 4
Offset: 1

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Author

Clark Kimberling, Apr 13 2015

Keywords

Comments

See A256789 for definitions.

Examples

			R(1) = 1, positive part 1, nonpositive part 0;
R(2) = 4 - 2, positive part 4, nonpositive part 2;
R(3) = 4 - 1, positive part 4, nonpositive part 1;
R(89) = 100 - 16 + 9 - 4, positive part 100 + 9 = 109, nonpositive part 16 + 4 = 20.
		

Crossrefs

Programs

  • Mathematica
    b[n_] := n^2; bb = Table[b[n], {n, 0, 100}];
    s[n_] := Table[b[n], {k, 1, 2 n - 1}];
    h[1] = {1}; h[n_] := Join[h[n - 1], s[n]];
    g = h[100]; r[0] = {0}; r[1] = {1}; r[2] = {4, -2};
    r[n_] := If[MemberQ[bb, n], {n}, Join[{g[[n]]}, -r[g[[n]] - n]]];
    t = Table[r[n], {n, 1, z}] (* A256789 *)
    Table[Total[(Abs[r[n]] + r[n])/2], {n, 1, 120}]  (* A256796 *)
    Table[Total[(Abs[r[n]] - r[n])/2], {n, 1, 120}]  (* A256797 *)