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.

A241597 Number of compositions corresponding to the n-th partition in A241596 (or A242628).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 3, 3, 1, 1, 1, 2, 1, 2, 3, 3, 1, 2, 3, 6, 4, 3, 6, 4, 1, 1, 1, 2, 1, 2, 3, 3, 1, 2, 3, 6, 4, 3, 6, 4, 1, 2, 3, 6, 4, 6, 12, 12, 5, 3, 6, 12, 10, 4, 10, 5, 1
Offset: 1

Views

Author

N. J. A. Sloane, May 19 2014

Keywords

Examples

			If arranged in a triangle to match A241596, the terms are:
1,
1,1,
1,1,2,1,
1,1,2,1,2,3,3,1,
1,1,2,1,2,3,3,1,2,3,6,4,3,6,4,1,1,1,2,1,2,3,3,1,2,3,6,4,3,6,4,1,2,3,6,4,6,12,12,5,3,6,12,10,4,10,5,1,
...
		

Crossrefs

A242628 Irregular table enumerating partitions; n-th row has partitions in previous row with each part incremented, followed by partitions in previous row with an additional part of size 1.

Original entry on oeis.org

1, 2, 1, 1, 3, 2, 2, 2, 1, 1, 1, 1, 4, 3, 3, 3, 2, 2, 2, 2, 3, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 5, 4, 4, 4, 3, 3, 3, 3, 4, 2, 3, 3, 2, 3, 2, 2, 2, 2, 2, 2, 4, 1, 3, 3, 1, 3, 2, 1, 2, 2, 2, 1, 3, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 6, 5, 5, 5, 4, 4, 4, 4, 5, 3, 4, 4, 3, 4, 3, 3, 3, 3, 3, 3, 5, 2
Offset: 1

Views

Author

Keywords

Comments

This can be calculated using the binary expansion of n; see the PARI program.
The n-th row consists of all partitions with hook size (maximum + number of parts - 1) equal to n.
The partitions in row n of this sequence are the conjugates of the partitions in row n of A125106 taken in reverse order.
Row n is also the reversed partial sums plus one of the n-th composition in standard order (A066099) minus one. - Gus Wiseman, Nov 07 2022

Examples

			The table starts:
  1;
  2; 1,1;
  3; 2,2; 2,1; 1,1,1;
  4; 3,3; 3,2; 2,2,2; 3,1 2,2,1 2,1,1 1,1,1,1;
  ...
		

Crossrefs

Cf. A241596 (another version of this list of partitions), A125106, A240837, A112531, A241597 (compositions).
For other schemes to list integer partitions, please see for example A227739, A112798, A241918, A114994.
First element in each row is A008687.
Last element in each row is A065120.
Heinz numbers of rows are A253565.
Another version is A358134.

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=1, [[1]],
          [map(x-> map(y-> y+1, x), b(n-1))[],
           map(x-> [x[], 1], b(n-1))[]])
        end:
    T:= n-> map(x-> x[], b(n))[]:
    seq(T(n), n=1..7);  # Alois P. Heinz, Sep 25 2015
  • Mathematica
    T[1] = {{1}};
    T[n_] := T[n] = Join[T[n-1]+1, Append[#, 1]& /@ T[n-1]];
    Array[T, 7] // Flatten (* Jean-François Alcover, Jan 25 2021 *)
  • PARI
    apart(n) = local(r=[1]); while(n>1,if(n%2==0,for(k=1,#r,r[k]++),r=concat(r,[1]));n\=2);r \\ Generates n-th partition.

A112531 Triangle read by rows which lists compositions having at least one part equal to 1.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 3, 1, 2, 3, 6, 4, 3, 6, 4, 1, 2, 3, 6, 4, 6, 12, 12, 5, 3, 6, 12, 10, 4, 10, 5, 1, 2, 3, 6, 4, 6, 12, 12, 5, 6, 12, 24, 20, 12, 30, 20, 6, 3, 6, 12, 10, 12, 30, 30, 15, 4, 10, 20, 20, 5, 15, 6, 1
Offset: 1

Views

Author

Alford Arnold, Sep 10 2005

Keywords

Comments

Consider partitions listed in the order given by A241596 and A242628. Omit any partition not containing 1 as a part. Write down the number of compositions (= ordered partitions) corresponding to this partition.
Row sums give A112532; which are the first differences of A047970.
Row lengths give A011782.

Examples

			The partitions (see A241596) begin 1 2 11 3 22 21 111 4 33 32 222 31 221 211 1111 ...
After omitting partitions with no part equal to 1, we have
1 11 21 111 31 221 211 1111 ...
which give rise to 1 1 2 1 2 3 3 1 ... compositions.
The resulting triangle of compositions begins:
1;
1;
2, 1;
2, 3, 3, 1;
2, 3, 6, 4, 3, 6, 4, 1;
2, 3, 6, 4, 6, 12, 12, 5, 3, 6, 12, 10, 4, 10, 5, 1;
2, 3, 6, 4, 6, 12, 12, 5, 6, 12, 24, 20, 12, 30, 20, 6, 3, 6, 12, 10, 12, 30, 30, 15, 4, 10, 20, 20, 5, 15, 6, 1;
...
		

Crossrefs

Extensions

Edited by N. J. A. Sloane, May 19 2014 based on postings to the Sequence Fans Mailing List by Peter Luschny, Jonas Wallgren, Arie Groeneveld, and Franklin T. Adams-Watters.
Showing 1-3 of 3 results.