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 1-4 of 4 results.

A293402 The integer k that minimizes |k/n^2 - tau|, where tau = (1+sqrt(5))/2 (golden ratio).

Original entry on oeis.org

0, 2, 6, 15, 26, 40, 58, 79, 104, 131, 162, 196, 233, 273, 317, 364, 414, 468, 524, 584, 647, 714, 783, 856, 932, 1011, 1094, 1180, 1269, 1361, 1456, 1555, 1657, 1762, 1870, 1982, 2097, 2215, 2336, 2461, 2589
Offset: 0

Views

Author

Clark Kimberling, Oct 11 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 120; r = GoldenRatio;
    Table[Floor[r*n^2], {n, 0, z}];   (* A293400 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293401 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293402 *)

Formula

a(n) = floor(1/2 + tau*n^2).
a(n) = A293400(n) if (fractional part of tau*n^2) < 1/2, else a(n) = A293401(n).

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.

A293400 Greatest integer k such that k/n^2 < (1 + sqrt(5))/2 (the golden ratio).

Original entry on oeis.org

0, 1, 6, 14, 25, 40, 58, 79, 103, 131, 161, 195, 232, 273, 317, 364, 414, 467, 524, 584, 647, 713, 783, 855, 931, 1011, 1093, 1179, 1268, 1360, 1456, 1554, 1656, 1762, 1870, 1982, 2096, 2215, 2336, 2461, 2588
Offset: 0

Views

Author

Clark Kimberling, Oct 11 2017

Keywords

Crossrefs

Programs

  • Magma
    [Floor((1 + Sqrt(5))/2*n^2) : n in [0..80]]; // Wesley Ivan Hurt, Jul 03 2020
  • Mathematica
    z = 120; r = GoldenRatio;
    Table[Floor[r*n^2], {n, 0, z}];   (* A293400 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293401 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293402 *)

Formula

a(n) = floor(r*n^2), where r = (1 + sqrt(5))/2.
a(n) = A293401(n) - 1 for n > 0.

A293407 Least integer k such that k/n^2 > (-1 + sqrt(5))/2 (the golden ratio).

Original entry on oeis.org

0, 1, 3, 6, 10, 16, 23, 31, 40, 51, 62, 75, 89, 105, 122, 140, 159, 179, 201, 224, 248, 273, 300, 327, 356, 387, 418, 451, 485, 520, 557, 594, 633, 674, 715, 758, 801, 847, 893, 941, 989, 1039, 1091, 1143, 1197, 1252, 1308, 1366, 1424, 1484, 1546, 1608, 1672
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}];   (* A152738 *)
    Table[Ceiling[r*n^2], {n, 0, z}]; (* A293407 *)
    Table[Round[r*n^2], {n, 0, z}];   (* A293408 *)

Formula

a(n) = ceiling(r*n^2), where r = (-1 + sqrt(5))/2.
a(n) = A152738(n) + 1 for n > 0.
Showing 1-4 of 4 results.