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 1-5 of 5 results.

A376370 Square array read by antidiagonals: row n lists numbers that occur exactly n times in A036038 (or A050382 or A078760 or A318762), i.e., numbers m such that the multinomial coefficient (x_1 + ... + x_k)!/(x_1! * ... * x_k!) is equal to m for exactly n integer partitions (x_1, ..., x_k).

Original entry on oeis.org

2, 3, 10, 4, 12, 6, 5, 15, 20, 420, 7, 21, 30, 630, 120, 8, 24, 56, 840, 1680, 210, 9, 28, 60, 1980, 60060, 1260, 4324320, 11, 35, 90, 3003, 83160, 2520, 21621600, 7207200, 13, 36, 105, 7140, 180180, 5040, 24504480, 151351200, 720720
Offset: 1

Views

Author

Pontus von Brömssen, Sep 22 2024

Keywords

Comments

Row n lists numbers m such that A376369(m) = n.
In case there are only finitely many solutions for a certain value of n, the rest of that row is filled with 0's.
Any integer k >= 2 appears exactly once in the array.

Examples

			Array begins:
  n\k|       1         2         3         4         5          6          7          8
  ---+---------------------------------------------------------------------------------
  1  |       2         3         4         5         7          8          9         11
  2  |      10        12        15        21        24         28         35         36
  3  |       6        20        30        56        60         90        105        252
  4  |     420       630       840      1980      3003       7140       7560       9240
  5  |     120      1680     60060     83160    180180     240240     831600     900900
  6  |     210      1260      2520      5040     27720     166320    1441440    4084080
  7  | 4324320  21621600  24504480  43243200  75675600  116396280  367567200  908107200
  8  | 7207200 151351200 302702400 411863760 823727520 1816214400 2327925600 4655851200
		

Crossrefs

Cf. A036038, A050382, A078760, A318762, A325472 (complement of first row), A325593 (complement of the union of the first 2 rows), A376369, A376376 (first column).
First five rows are A376371, A376372, A376373, A376374, A376375.

A376673 Least number whose maximum frequency in a fixed row of A036038 (or A078760) is equal to n, i.e., least number m such that A376663(m) = n, or 0 if no such number exists.

Original entry on oeis.org

1, 56, 166320, 4084080, 1396755360, 698377680, 146659312800, 1075501627200, 37104806138400, 3710480613840000, 296838449107200, 86825246363856000, 96472495959840000, 36466603472819520000, 35251050023725536000, 272194921062320256000, 408292381593480384000
Offset: 1

Views

Author

Pontus von Brömssen, Oct 02 2024

Keywords

Comments

After a(36), the sequence continues (where "?" represents terms that are either 0 or greater than 10^29): ?, 3059734941813910128088320000, ?, ?, 64254433778092112689854720000. After a(41), all terms are either 0 or greater than 10^29.
The terms a(1), a(3), ..., a(15), a(24), a(26), ..., a(36), a(38), a(41) are all in A025487, but a(16), ..., a(23), a(25) are all divisible by 17^2 but not by 13^2.

Examples

			First few terms and their representations as multinomial coefficients (corresponding to partitions with sum A376664(n)):
  a(1) =          1 = 0!;
  a(2) =         56 = 8!/(1!*1!*6!) = 8!/(3!*5!);
  a(3) =     166320 = 12!/(1!*1!*1!*4!*5!) = 12!/(1!*1!*2!*2!*6!) = 12!/(2!*2!*3!*5!);
  a(4) =    4084080 = 17!/(1!*1!*1!*4!*10!) = 17!/(1!*2!*5!*9!) = 17!/(2!*2!*3!*10!) = 17!/(4!*6!*7!);
  a(5) = 1396755360 = 19!/(1!*1!*1!*1!*1!*4!*10!) = 19!/(1!*1!*1!*2!*5!*9!) = 19!/(1!*1!*2!*2!*3!*10!) = 19!/(1!*1!*4!*6!*7!) = 19!/(3!*4!*5!*7!).
		

Crossrefs

First column of A376667.

A376378 Indices of records in A376369.

Original entry on oeis.org

2, 6, 120, 210, 360360, 6983776800, 9777287520, 13967553600, 48886437600, 195545750400, 293318625600, 148419224553600, 296838449107200, 868252463638560000, 4002866486210592000, 8005732972421184000, 68048730265580064000, 136097460531160128000, 4082923815934803840000
Offset: 1

Views

Author

Pontus von Brömssen, Sep 23 2024

Keywords

Crossrefs

Formula

a(n) = A376376(A376377(n)).

A376377 Records in A376369.

Original entry on oeis.org

1, 3, 5, 6, 10, 11, 12, 13, 14, 15, 18, 19, 22, 24, 25, 28, 31, 37, 44, 50, 51, 52, 57, 59, 60, 62, 67, 69
Offset: 1

Views

Author

Pontus von Brömssen, Sep 23 2024

Keywords

Crossrefs

Formula

a(n) = A376369(A376378(n)).

A376866 a(n) = smallest integer k >= 2 such that there exist n disjoint multisets of positive integers, whose corresponding multinomial coefficients equal k.

Original entry on oeis.org

2, 6, 120, 3003, 433866230594439538896000
Offset: 1

Views

Author

Pontus von Brömssen, Oct 07 2024

Keywords

Examples

			  n |                     a(n) | disjoint multisets with multinomial coefficient a(n)
  --+--------------------------+---------------------------------------------
  1 |                        2 | {1,1}
  2 |                        6 | {2,2}, {1,5}
  3 |                      120 | {3,7}, {2,14}, {1,119}
  4 |                     3003 | {6,8}, {5,10}, {2,76}, {1,3002}
  5 | 433866230594439538896000 | {4,9,13,23}, {2,2,8,11,27}, {3,3,3,16,25}, {5,6,15,24},
    |                          | {1,433866230594439538895999}
		

Crossrefs

Extensions

Edited by Max Alekseyev, May 18 2025
Showing 1-5 of 5 results.