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 1-2 of 2 results.

A239512 Irregular triangular array read by rows: row n gives a list of the partitions of the Lucas numbers.

Original entry on oeis.org

1, 2, 1, 1, 3, 2, 1, 1, 1, 1, 4, 3, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 4, 1, 3, 2, 3, 1, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 4, 2, 4, 1, 1, 3, 3, 3, 2, 1, 3, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 4, 3, 4, 2, 1, 4, 1, 1, 1, 3, 3, 1
Offset: 1

Views

Author

Clark Kimberling, Mar 25 2014

Keywords

Comments

The number of partitions represented in row n is A067592(n). The parts of each partition are arranged in nonincreasing order, and the partitions are arranged in Mathematica order (reverse-lexicographic). The parts are the terms of the Lucas sequence, A000032(n), n >= 1.

Examples

			The first 7 rows:
1
1 1
3 1 1 1
4 3 1 1 1 1 1
4 1 3 1 1 1 1 1 1 1
4 1 1 3 3 3 1 1 1 1 1 1 1 1 1
7 4 3 4 1 1 1 3 3 1 3 1 1 1 1 1 1 1 1 1 1 1
The first 7 rows represent these partitions:
1
11
3, 111
4, 31, 1111
41, 311, 11111
411, 33, 3111, 111111
7, 43, 431, 41111, 3311, 311111, 1111111
		

Crossrefs

Programs

  • Mathematica
    LucasQ[n_] := IntegerQ[Sqrt[5 n^2 + 20]] || IntegerQ[Sqrt[5 n^2 - 20]];
    Attributes[LucasQ] = {Listable}; TableForm[t = Map[Select[IntegerPartitions[#], And @@ LucasQ[#] &] &, Range[0, 12]]]  (* A239512, partitions *)
    Flatten[t] (* A067592 *)
    (* Peter J. C. Moses, Mar 24 2014 *)

A240224 Irregular triangular array read by rows: row n gives a list of the partitions of n into distinct Fibonacci numbers. The order of the partitions is like in Abramowitz-Stegun.

Original entry on oeis.org

1, 2, 3, 2, 1, 3, 1, 5, 3, 2, 5, 1, 3, 2, 1, 5, 2, 8, 5, 3, 5, 2, 1, 8, 1, 5, 3, 1, 8, 2, 5, 3, 2, 8, 3, 8, 2, 1, 5, 3, 2, 1, 8, 3, 1, 13, 8, 5, 8, 3, 2, 13, 1, 8, 5, 1, 8, 3, 2, 1, 13, 2, 8, 5, 2, 13, 3, 13, 2, 1, 8, 5, 3, 8, 5, 2, 1, 13, 3, 1, 8, 5, 3, 1, 13, 5, 13, 3, 2, 8, 5, 3, 2, 13, 5, 1, 13, 3, 2, 1, 8, 5, 3, 2, 1, 13, 5, 2
Offset: 1

Views

Author

Wolfdieter Lang, Apr 07 2014

Keywords

Comments

The row length sequence is A240225. The number of partitions in row n is A000119(n).
The order of the partitions is like in Abramowitz-Stegun (rising number of parts, within like part numbers lexicographic) but here the order of the parts has been reversed, that is they are ordered decreasingly.

Examples

			The array with separated partitions begins:
n\k       1         2          3         4            5 ...
1:        1
2:        2
3:        3       2,1
4:      3,1
5:        5       3,2
6:      5,1     3,2,1
7:      5,2
8:        8       5,3      5,2,1
9:      8,1     5,3,1
10:     8,2     5,3,2
11:     8,3     8,2,1    5,3,2,1
12:   8,3,1
13:      13       8,5      8,3,2
14:    13,1     8,5,1    8,3,2,1
15:    13,2     8,5,2
16:    13,3    13,2,1      8,5,3   8,5,2,1
17:  13,3,1   8,5,3,1
18:    13,5    13,3,2    8,5,3,2
19:  13,5,1  13,3,2,1  8,5,3,2,1
20:  13,5,2
21:      21      13,8     13,5,3  13,5,2,1
22:    21,1    13,8,1   13,5,3,1
23:    21,2    13,8,2   13,5,3,2
24:    21,3    21,2,1     13,8,3  13,8,2,1   13,5,3,2,1
25:  21,3,1  13,8,3,1
...
		

Crossrefs

Showing 1-2 of 2 results.