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.

User: Christian Stump

Christian Stump's wiki page.

Christian Stump has authored 57 sequences. Here are the ten most recent ones:

A298248 Triangle of double-Eulerian numbers DE(n,k) (n >= 0, 0 <= k <= max(0, 2*(n-1))) read by rows.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 0, 4, 0, 1, 1, 0, 10, 2, 10, 0, 1, 1, 0, 20, 12, 54, 12, 20, 0, 1, 1, 0, 35, 42, 212, 140, 212, 42, 35, 0, 1, 1, 0, 56, 112, 675, 880, 1592, 880, 675, 112, 56, 0, 1, 1, 0, 84, 252, 1845, 3962, 9246, 9540, 9246, 3962, 1845, 252, 84, 0, 1
Offset: 0

Author

Christian Stump, Jan 16 2018

Keywords

Comments

DE(n,k) = number of permutations with d descents and e descents of the inverse such that d+e = k.

Examples

			The triangle DE(n, k) begins:
n\k 0    1     2     3      4      5      6     7     8    9   10
0:  1
1:  1
2:  1    0     1
3:  1    0     4     0      1
4:  1    0    10     2     10      0      1
5:  1    0    20    12     54     12     20     0     1
6:  1    0    35    42    212    140    212    42    35    0    1
		

References

  • Christian Stump, On bijections between 231-avoiding permutations and Dyck paths, MathSciNet:2734176

Crossrefs

Row sums give A000142.

Programs

  • SageMath
    q = var("q")
    [sum( q^(pi.number_of_descents()+pi.inverse().number_of_descents()) for pi in Permutations(n) ).coefficients(sparse=False) for n in [1 .. 6]]

A273254 Dimensions of odd-dimensional spheres with unique smooth structure.

Original entry on oeis.org

1, 3, 5, 61
Offset: 1

Author

Christian Stump, May 18 2016

Keywords

A264049 Triangle read by rows: T(n,k) (n>=1, k>=1) is the number of integer partitions lambda of n such that there are k partitions mu such that the Gelfand-Tsetlin polytope for lambda and mu is integral.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 2, 0, 1, 1, 1, 2, 1, 2, 0, 1, 1, 1, 0, 1, 1, 1, 3, 0, 2, 2, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 3, 2, 2, 2, 0, 2, 0, 3, 0, 0, 2, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1
Offset: 1

Author

Christian Stump, Nov 02 2015

Keywords

Comments

Row sums give A000041, n >= 1.

Examples

			Triangle begins:
1,
1,1,
1,1,1,
1,1,1,1,1,
1,2,0,2,0,1,1,
1,2,1,2,0,1,1,1,0,1,1,
1,3,0,2,2,1,1,1,0,0,1,1,0,1,1,
1,3,2,2,2,0,2,0,3,0,0,2,0,0,1,0,1,0,1,0,1,1,
...
		

Crossrefs

A264048 Triangle read by rows: T(n,k) (n>=1, k>=1) is the number of integer partitions lambda of n such that there are k compositions mu such that the Gelfand-Tsetlin polytope for lambda and mu is integral.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1
Offset: 1

Author

Christian Stump, Nov 02 2015

Keywords

Comments

Row sums give A000041, n >= 1.

Examples

			Triangle begins:
1,
1,1,
1,0,1,1,
1,0,0,1,1,0,1,1,
1,0,0,0,1,0,1,0,0,0,1,1,0,0,1,1,
1,0,0,0,0,1,0,0,0,0,1,1,0,0,0,1,1,0,0,0,0,0,1,0,0,2,0,0,0,0,1,1,
...
		

Crossrefs

A264047 Triangle read by rows: T(n,k) (n>=0, k>=0) is the number of integer partitions lambda of n such that there are k compositions mu such that the Gelfand-Tsetlin polytope for lambda and mu is non-integral.

Original entry on oeis.org

1, 1, 2, 3, 5, 5, 2, 6, 3, 0, 1, 0, 0, 1, 7, 1, 0, 0, 0, 0, 0, 2, 2, 0, 0, 1, 0, 0, 0, 0, 1, 1, 8, 1, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Author

Christian Stump, Nov 01 2015

Keywords

Comments

Row sums give A000041.

Examples

			Triangle begins:
1,
1,
2,
3,
5,
5,2,
6,3,0,1,0,0,1,
7,1,0,0,0,0,0,2,2,0,0,1,0,0,0,0,1,1,
8,1,0,0,0,0,0,0,2,0,0,1,0,0,1,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,1,2,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,
...
		

Crossrefs

A264035 Triangle read by rows: T(n,k) (n>=0, k>=0) is the number of integer partitions lambda of n such that there are k partitions mu such that the Gelfand-Tsetlin polytope for lambda and mu is non-integral.

Original entry on oeis.org

1, 1, 2, 3, 5, 5, 2, 6, 4, 1, 7, 2, 3, 2, 1, 8, 2, 3, 2, 3, 3, 0, 1
Offset: 0

Author

Christian Stump, Nov 01 2015

Keywords

Comments

Row sums give A000041.

Examples

			Triangle begins:
1,
1,
2,
3,
5,
5,2,
6,4,1,
7,2,3,2,1,
8,2,3,2,3,3,0,1,
...
		

Crossrefs

A264032 Triangle read by rows: T(n,k) (n>=0, k>=n+1) is the number of integer partitions of n containing exactly k partitions.

Original entry on oeis.org

1, 1, 2, 2, 1, 2, 1, 2, 2, 0, 0, 4, 1, 2, 0, 0, 2, 2, 2, 2, 1, 2, 0, 0, 0, 0, 2, 2, 2, 4, 1, 0, 2, 2, 0, 0, 0, 0, 0, 4, 0, 0, 4, 3, 0, 2, 2, 2, 2, 0, 1, 2, 0, 0, 0, 0, 0, 0, 2, 0, 0, 3, 2, 4, 0, 0, 4, 1, 0, 4, 2, 2, 0, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 2, 4, 2, 0, 0, 2, 2, 4, 0, 0, 6, 2, 0, 4
Offset: 0

Author

Christian Stump, Nov 01 2015

Keywords

Comments

Row sums give A000041.

Examples

			Triangle begins:
1,
1,
2,
2,1,
2,1,2,
2,0,0,4,1,
2,0,0,2,2,2,2,1,
2,0,0,0,0,2,2,2,4,1,0,2,
2,0,0,0,0,0,4,0,0,4,3,0,2,2,2,2,0,1,
2,0,0,0,0,0,0,2,0,0,3,2,4,0,0,4,1,0,4,2,2,0,2,2,
...
		

Crossrefs

Cf. A000041.

A263776 Triangle read by rows: T(n,k) (n>=0, 0<=k<=A002620(n-1)) is the number of permutations of [n] with k nestings.

Original entry on oeis.org

1, 1, 2, 5, 1, 14, 8, 2, 42, 45, 25, 7, 1, 132, 220, 198, 112, 44, 12, 2, 429, 1001, 1274, 1092, 700, 352, 140, 42, 9, 1, 1430, 4368, 7280, 8400, 7460, 5392, 3262, 1664, 716, 256, 74, 16, 2, 4862, 18564, 38556, 56100, 63648, 59670, 47802, 33338, 20466, 11115
Offset: 0

Author

Christian Stump, Oct 26 2015

Keywords

Comments

Row sums give A000142.
First column gives A000108.
Also the number of permutations of [n] with k crossings (see Corteel, Proposition 4).
Also the number of permutations of [n] with exactly k (possibly overlapping) occurrences of the generalized pattern 13-2 (alternatively: 2-13, 2-31, or 31-2). - Alois P. Heinz, Nov 14 2015

Examples

			Triangle begins:
0 :   1;
1 :   1;
2 :   2;
3 :   5,    1;
4 :  14,    8,    2;
5 :  42,   45,   25,    7,   1;
6 : 132,  220,  198,  112,  44,  12,   2;
7 : 429, 1001, 1274, 1092, 700, 352, 140, 42, 9, 1;
...
		

Programs

  • Maple
    b:= proc(u, o) option remember;
          `if`(u+o=0, 1, add(b(u-j, o+j-1), j=1..u)+
           add(expand(b(u+j-1, o-j)*x^(j-1)), j=1..o))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n, 0)):
    seq(T(n), n=0..10);  # Alois P. Heinz, Nov 14 2015
  • Mathematica
    b[u_, o_] := b[u, o] = If[u+o == 0, 1, Sum[b[u-j, o+j-1], {j, 1, u}] + Sum[Expand[b[u+j-1, o-j]*x^(j-1)], {j, 1, o}]]; T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][b[n, 0]]; Table[ T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Jan 31 2016, after Alois P. Heinz *)

Formula

Sum_{k>0} k * T(n,k) = A001754(n).
T(n,n) = A287328(n). - Alois P. Heinz, Aug 31 2017

Extensions

More terms from Alois P. Heinz, Oct 26 2015

A264034 Triangle read by rows: T(n,k) (n>=0, 0<=k<=A161680(n)) is the number of integer partitions of n with weighted sum k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1, 2, 1, 0, 2, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 2, 1, 1, 2, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 1, 3, 2, 1
Offset: 0

Author

Christian Stump, Nov 01 2015

Keywords

Comments

Row sums give A000041.
The weighted sum is given by the sum of the rows where row i is weighted by i.
Note that the first part has weight 0. This statistic (zero-based weighted sum) is ranked by A359677, reverse A359674. Also the number of partitions of n with one-based weighted sum n + k. - Gus Wiseman, Jan 10 2023

Examples

			Triangle T(n,k) begins:
  1;
  1;
  1,1;
  1,1,0,1;
  1,1,1,1,0,0,1;
  1,1,1,1,1,0,1,0,0,0,1;
  1,1,1,2,1,0,2,1,0,0,1,0,0,0,0,1;
  1,1,1,2,1,1,2,1,0,1,1,1,0,0,0,1,0,0,0,0,0,1;
  1,1,1,2,2,1,2,2,1,1,1,1,1,1,0,1,1,0,0,0,0,1,0,0,0,0,0,0,1;
  ...
The a(15,31) = 5 partitions of 15 with weighted sum 31 are: (6,2,2,1,1,1,1,1), (5,4,1,1,1,1,1,1), (5,2,2,2,2,1,1), (4,3,2,2,2,2), (3,3,3,3,2,1). These are also the partitions of 15 with one-based weighted sum 46. - _Gus Wiseman_, Jan 09 2023
		

Crossrefs

Row sums are A000041.
The version for compositions is A053632, ranked by A124757 (reverse A231204).
Row lengths are A152947, or A161680 plus 1.
The one-based version is also A264034, if we use k = n..n(n+1)/2.
The reverse version A358194 counts partitions by sum of partial sums.
A359677 gives zero-based weighted sum of prime indices, reverse A359674.
A359678 counts multisets by zero-based weighted sum.

Programs

  • Maple
    b:= proc(n, i, w) option remember; expand(
          `if`(n=0, 1, `if`(i<1, 0, b(n, i-1, w)+
          `if`(i>n, 0, x^(w*i)*b(n-i, i, w+1)))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n$2, 0)):
    seq(T(n), n=0..10);  # Alois P. Heinz, Nov 01 2015
  • Mathematica
    b[n_, i_, w_] := b[n, i, w] = Expand[If[n == 0, 1, If[i < 1, 0, b[n, i - 1, w] + If[i > n, 0, x^(w*i)*b[n - i, i, w + 1]]]]]; T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][b[n, n, 0]]; Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Feb 07 2017, after Alois P. Heinz *)
    Table[Length[Select[IntegerPartitions[n],Total[Accumulate[Reverse[#]]]==k&]],{n,0,8},{k,n,n*(n+1)/2}] (* Gus Wiseman, Jan 09 2023 *)

Formula

From Alois P. Heinz, Jan 20 2023: (Start)
max_{k=0..A161680(n)} T(n,k) = A337206(n).
Sum_{k=0..A161680(n)} k * T(n,k) = A066185(n). (End)

A264051 Triangle read by rows: T(n,k) (n>=0, 0<=k<=A264078(n)) is the number of integer partitions of n having k standard Young tableaux such that no entries i and i+1 appear in the same row.

Original entry on oeis.org

0, 1, 0, 1, 1, 1, 1, 2, 2, 2, 1, 2, 3, 0, 2, 4, 2, 1, 1, 1, 1, 1, 4, 3, 1, 0, 0, 2, 2, 0, 1, 0, 1, 0, 0, 0, 1, 7, 2, 0, 0, 1, 0, 3, 0, 1, 0, 2, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 7, 3, 1, 2, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1
Offset: 0

Author

Christian Stump, Nov 01 2015

Keywords

Comments

Row sums give A000041.
Column k=0 gives A025065(n-2) for n>=2.

Examples

			Triangle begins:
0,1,
0,1,
1,1,
1,2,
2,2,1,
2,3,0,2,
4,2,1,1,1,1,1,
4,3,1,0,0,2,2,0,1,0,1,0,0,0,1,
7,2,0,0,1,0,3,0,1,0,2,1,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,
...
		

Crossrefs

Programs

  • Maple
    h:= proc(l, j) option remember; `if`(l=[], 1,
          `if`(l[1]=0, h(subsop(1=[][], l), j-1), add(
          `if`(i<>j and l[i]>0 and (i=1 or l[i]>l[i-1]),
           h(subsop(i=l[i]-1, l), i), 0), i=1..nops(l))))
        end:
    g:= proc(n, i, l) `if`(n=0 or i=1, x^h([1$n, l[]], 0),
          `if`(i<1, 0, g(n, i-1, l)+ `if`(i>n, 0,
           g(n-i, i, [i, l[]]))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(g(n$2, [])):
    seq(T(n), n=0..10);  # Alois P. Heinz, Nov 02 2015
  • Mathematica
    h[l_, j_] := h[l, j] = If[l == {}, 1, If[l[[1]] == 0, h[ReplacePart[l, 1 -> Sequence[]], j - 1], Sum[If[i != j && l[[i]] > 0 && (i == 1 || l[[i]] > l[[i - 1]]), h[ReplacePart[l, i -> l[[i]] - 1], i], 0], {i, 1, Length[l]} ]]]; g[n_, i_, l_] := If[n == 0 || i == 1, x^h[Join[Array[1 &, n], l], 0], If[i < 1, 0, g[n, i - 1, l] + If[i > n, 0, g[n - i, i, Join[{i}, l]]] ]]; T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][g[n, n, {}]]; Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Jan 22 2016, after Alois P. Heinz *)

Formula

Sum_{k=1..A264078(n)} k*T(n,k) = A237770(n). - Alois P. Heinz, Nov 02 2015