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.

A050210 Largest denominator in unit fraction representation of triangle of numbers 1/2, 1/3, 2/3, 1/4, 2/4, ... as computed with greedy algorithm.

Original entry on oeis.org

2, 3, 6, 4, 2, 4, 5, 15, 10, 20, 6, 3, 2, 6, 3, 7, 28, 231, 14, 70, 42, 8, 4, 24, 2, 8, 4, 24, 9, 45, 3, 9, 18, 6, 36, 18, 10, 5, 20, 15, 2, 10, 5, 20, 15, 11, 66, 44, 33, 99, 22, 88, 4070, 660, 231, 12, 6, 4, 3, 12, 2, 12, 6, 4, 3, 12, 13, 91, 2145, 468, 780, 312, 26, 234, 39, 52, 78, 156
Offset: 2

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Author

Keywords

Examples

			Triangle begins:
   2;
   3,  6;
   4,  2,   4;
   5, 15,  10, 20;
   6,  3,   2,  6,  3;
   7, 28, 231, 14, 70, 42;
   8,  4,  24,  2,  8,  4, 24;
   9, 45,   3,  9, 18,  6, 36,   18;
  10,  5,  20, 15,  2, 10,  5,   20,  15;
  11, 66,  44, 33, 99, 22, 88, 4070, 660, 231;
  ...
		

Crossrefs

Extensions

Offset changed to 2 by Alois P. Heinz, Sep 25 2014

A050206 Triangle read by rows: smallest denominator of the expansion of k/n using the greedy algorithm, 1<=k<=n-1.

Original entry on oeis.org

2, 3, 2, 4, 2, 2, 5, 3, 2, 2, 6, 3, 2, 2, 2, 7, 4, 3, 2, 2, 2, 8, 4, 3, 2, 2, 2, 2, 9, 5, 3, 3, 2, 2, 2, 2, 10, 5, 4, 3, 2, 2, 2, 2, 2, 11, 6, 4, 3, 3, 2, 2, 2, 2, 2, 12, 6, 4, 3, 3, 2, 2, 2, 2, 2, 2, 13, 7, 5, 4, 3, 3, 2, 2, 2, 2, 2, 2, 14, 7, 5, 4, 3, 3, 2, 2, 2, 2, 2, 2, 2, 15, 8, 5, 4, 3, 3, 3, 2
Offset: 2

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Author

Keywords

Examples

			n\k | 1  2  3  4  5  6  7  8
----*------------------------
  2 | 2;
  3 | 3, 2;
  4 | 4, 2, 2;
  5 | 5, 3, 2, 2;
  6 | 6, 3, 2, 2, 2;
  7 | 7, 4, 3, 2, 2, 2;
  8 | 8, 4, 3, 2, 2, 2, 2;
  9 | 9, 5, 3, 3, 2, 2, 2, 2;
		

Crossrefs

Cf. A050205, A050210 (Largest denominator), A260618.

Formula

T(n,k) = ceiling(n/k).

Extensions

Offset changed to 2 by Seiichi Manyama, Sep 18 2022

A260618 Irregular triangle read by rows: denominators of the expansion of k/n using the greedy algorithm, 1<=k<=n.

Original entry on oeis.org

1, 2, 1, 3, 2, 6, 1, 4, 2, 2, 4, 1, 5, 3, 15, 2, 10, 2, 4, 20, 1, 6, 3, 2, 2, 6, 2, 3, 1, 7, 4, 28, 3, 11, 231, 2, 14, 2, 5, 70, 2, 3, 42, 1, 8, 4, 3, 24, 2, 2, 8, 2, 4, 2, 3, 24, 1, 9, 5, 45, 3, 3, 9, 2, 18, 2, 6, 2, 4, 36, 2, 3, 18, 1, 10, 5, 4, 20, 3, 15, 2, 2, 10, 2, 5, 2, 4, 20, 2, 3, 15, 1, 11, 6, 66, 4, 44, 3, 33, 3, 9, 99, 2, 22, 2, 8, 88, 2, 5, 37, 4070, 2, 4, 15, 660, 2, 3, 14, 231, 1
Offset: 1

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Author

Matthew Campbell, Sep 17 2015

Keywords

Examples

			Triangle begins ({} included for fraction separation):
  {1};
  {2}, {1};
  {3}, {2, 6}, {1};
  {4}, {2}, {2, 4}, {1};
  {5}, {3, 15}, {2, 10}, {2, 4, 20}, {1};
  {6}, {3}, {2}, {2, 6}, {2, 3}, {1};
  {7}, {4, 28}, {3, 11, 231}, {2, 14}, {2, 5, 70}, {2, 3, 42}, {1};
  {8}, {4}, {3, 24}, {2}, {2, 8}, {2, 4}, {2, 3, 24}, {1};
  {9}, {5, 45}, {3}, {3, 9}, {2, 18}, {2, 6}, {2, 4, 36}, {2, 3, 18}, {1};
  {10}, {5}, {4, 20}, {3, 15}, {2}, {2, 10}, {2, 5}, {2, 4, 20}, {2, 3, 15}, {1};
  {11}, {6, 66}, {4, 44}, {3, 33}, {3, 9, 99}, {2, 22}, {2, 8, 88}, {2, 5, 37, 4070}, {2, 4, 15, 660}, {2, 3, 14, 231}, {1};
		

Crossrefs

Programs

  • PARI
    rep(f)={L=List(); while(f<>0, my(t=ceil(1/f)); listput(L,t); f-=1/t); Vec(L)}
    row(n)={concat(apply(k->rep(k/n), [1..n]))}
    for(n=1, 11, print(row(n))) \\ Andrew Howroyd, Feb 26 2018

A281530 Triangle read by rows: T(n,k) = number of terms for the shortest Egyptian fraction representation of k/n, 1 <= k < n.

Original entry on oeis.org

1, 1, 2, 1, 1, 2, 1, 2, 2, 3, 1, 1, 1, 2, 2, 1, 2, 3, 2, 3, 3, 1, 1, 2, 1, 2, 2, 3, 1, 2, 1, 2, 2, 2, 3, 3, 1, 1, 2, 2, 1, 2, 2, 3, 3, 1, 2, 2, 2, 3, 2, 3, 4, 4, 4, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 3, 1, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 4, 1, 1, 2, 2, 2, 3, 1, 2, 2, 3, 3, 3, 4, 1, 2, 1, 2, 1, 2, 3, 2, 2, 2, 3, 3, 3, 3
Offset: 2

Views

Author

Arkadiusz Wesolowski, Jan 23 2017

Keywords

Comments

Not same as A050205. Example: the fraction 9/20 requires three terms in its greedy expansion, but 9/20 = 1/4 + 1/5, so T(20,9) = 2.

Examples

			The triangle T(n,k) begins:
2:                     1
3:                   1   2
4:                 1   1   2
5:               1   2   2   3
6:             1   1   1   2   2
7:           1   2   3   2   3   3
8:         1   1   2   1   2   2   3
9:       1   2   1   2   2   2   3   3
		

Crossrefs

Cf. A281527.
Showing 1-4 of 4 results.