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.

Showing 1-3 of 3 results.

A293403 Greatest integer k such that k/n^2 < (3 + sqrt(5))/2.

Original entry on oeis.org

0, 2, 10, 23, 41, 65, 94, 128, 167, 212, 261, 316, 376, 442, 513, 589, 670, 756, 848, 945, 1047, 1154, 1267, 1384, 1507, 1636, 1769, 1908, 2052, 2201, 2356, 2515, 2680, 2851, 3026, 3207, 3392, 3584, 3780, 3982, 4188, 4400, 4618, 4840, 5068, 5301, 5539, 5783
Offset: 0

Views

Author

Clark Kimberling, Oct 11 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 120; r = 1+GoldenRatio;
    Table[Floor[r*n^2], {n, 0, z}];   (* A293403 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293404 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293405 *)

Formula

a(n) = floor(r*n^2), where r = (3 + sqrt(5))/2.
a(n) = A293404(n) - 1 for n > 0.

A293405 The integer k that minimizes |k/n^2 - tau^2|, where tau = (1+sqrt(5))/2 (golden ratio).

Original entry on oeis.org

0, 3, 10, 24, 42, 65, 94, 128, 168, 212, 262, 317, 377, 442, 513, 589, 670, 757, 848, 945, 1047, 1155, 1267, 1385, 1508, 1636, 1770, 1909, 2053, 2202, 2356, 2516, 2681, 2851, 3026, 3207, 3393, 3584, 3780, 3982, 4189, 4401, 4618, 4841, 5069, 5302, 5540, 5783
Offset: 0

Views

Author

Clark Kimberling, Oct 11 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 120; r = 1+GoldenRatio;
    Table[Floor[r*n^2], {n, 0, z}];   (* A293403 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293404 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293405 *)

Formula

a(n) = floor(1/2 + tau*n^2).
a(n) = A293403(n) if (fractional part of (1+tau)*n^2) < 1/2, else a(n) = A293404(n).

A293408 The integer k that minimizes |k/n^2 - 1/tau|, where tau = (1+sqrt(5))/2 (golden ratio).

Original entry on oeis.org

0, 1, 2, 6, 10, 15, 22, 30, 40, 50, 62, 75, 89, 104, 121, 139, 158, 179, 200, 223, 247, 273, 299, 327, 356, 386, 418, 451, 485, 520, 556, 594, 633, 673, 714, 757, 801, 846, 892, 940, 989, 1039, 1090, 1143, 1197, 1252, 1308, 1365, 1424, 1484, 1545, 1608, 1671
Offset: 0

Views

Author

Clark Kimberling, Oct 11 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 120; r = -11+GoldenRatio;
    Table[Floor[r*n^2], {n, 0, z}];   (* A152738 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293407 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293408 *)

Formula

a(n) = floor(1/2 + (n^2)/tau).
a(n) = A152738(n) if (fractional part of (1/tau)*n^2) < 1/2, else a(n) = A293407(n).
Showing 1-3 of 3 results.