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 1-8 of 8 results.

A109672 Entries in 3-dimensional solids related to Prouhet-Tarry problem.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 3, 3, 1, 3, 6, 3, 3, 3, 1, 1, 2, 1, 1, 5, 5, 1, 2, 5, 2, 1, 1, 1, 1, 2, 5, 2, 1, 5, 5, 1, 1, 2, 1, 1, 3, 3, 3, 6, 3, 1, 3, 3, 1, 1, 4, 6, 4, 1, 4, 12, 12, 4, 6, 12, 6, 4, 4, 1, 1, 3, 3, 1, 1, 7, 12, 7, 1, 3, 12
Offset: 0

Views

Author

Philippe Deléham, Aug 07 2005

Keywords

Comments

Table of slices [n,k] of solids, read by antidiagonals, each slice [n,k] read by rows.
Slice [n,0] gives A046816.
Slice [0,k] gives A109649.
Slice [n,n] gives A109673.

Examples

			Slice [0,0]:
...1...
Slice [0,1]:
... 1 1 ...
.... 1 ....
Slice [1,0]:
.... 1 ....
... 1 1...
Slice [0,2]:
.. 1 2 1 ...
.... 2 2 ...
..... 1 .....
Slice [1,1]:
... 1 1 ...
.. 1 3 1..
... 1 1 ...
Slice [2,0]:
..... 1 .....
.... 2 2 ...
.. 1 2 1 ...
Slice [0,3]:
.. 1 3 3 1 ...
... 3 6 3 ....
.... 3 3 ......
..... 1 ........
Slice [1,2]:
... 1 2 1 ...
.. 1 5 5 1 ...
... 2 5 2 ...
.... 1 1 ...
Slice [2,1]:
.... 1 1 ...
... 2 5 2 ...
.. 1 5 5 1 ...
... 1 2 1 ...
Slice [3,0]:
..... 1 .....
.... 3 3 ....
... 3 6 3 ...
.. 1 3 3 1 ...
		

Formula

Sum of terms in 2D slice [n, k] is 3^(n+k); example : 1+2+1+1+5+5+1+2+5+2+1+127=3^(2+1) for slice [1, 2].

A109390 Entries in 3-dimensional solid related to Prouhet-Tarry problem.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 5, 2, 1, 5, 5, 1, 1, 2, 1, 1, 1, 3, 7, 3, 3, 12, 12, 3, 1, 7, 12, 7, 1, 1, 3, 3, 1, 1, 1, 4, 9, 4, 6, 22, 22, 6, 4, 22, 36, 22, 4, 1, 9, 22, 22, 9, 1, 1, 1, 5, 11, 5, 10, 35, 35, 10, 10, 50, 80, 50, 10, 5, 35, 80, 80, 35, 5, 1, 11, 35, 50
Offset: 0

Views

Author

Philippe Deléham, Aug 26 2005

Keywords

Comments

Entries of slices [n,1] in A109672, read by rows.
Slice [n,0] gives A046816, slice [0,k] gives A109649, slice [n,n] gives A109673, slice [1,k] gives A109393.

Examples

			Slice [0,1]:
... 1 1 ...
.... 1 ....
Slice [1,1]:
... 1 1 ...
.. 1 3 1 ...
... 1 1 ...
Slice [2,1]:
.... 1 1 ....
... 2 5 2 ...
.. 1 5 5 1 ...
... 1 2 1 ...
Slice [3,1]:
..... 1 1 .....
.... 3 7 3 ....
... 3 12 12 3 ...
.. 1 7 12 7 1 ...
... 1 3 3 1 ...
Slice [4,1]:
...... 1 1 ......
..... 4 9 4 .....
.... 6 22 22 6 ....
... 4 22 36 22 4 ...
.. 1 9 22 22 9 1 ...
... 1 4 6 4 1 ...
Slice [5,1]:
....... 1 1 .......
...... 5 11 5 ......
..... 10 35 35 10 .....
.... 10 50 80 50 10 ....
... 5 35 80 80 35 5 ...
.. 1 11 35 50 35 11 1 ...
... 1 5 10 10 5 1 ...
		

Crossrefs

Cf. A109393.

Formula

Sum of terms in 2D slice [n, 1] is 3^(n+1).

A109393 Entries in 3-dimensional solid related to Prouhet-Tarry problem.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 5, 5, 1, 2, 5, 2, 1, 1, 1, 3, 3, 1, 1, 7, 12, 7, 1, 3, 12, 12, 3, 3, 7, 3, 1, 1, 1, 4, 6, 4, 1, 1, 9, 22, 22, 9, 1, 4, 22, 36, 22, 4, 6, 22, 22, 6, 4, 9, 4, 1, 1, 1, 5, 10, 10, 5, 1, 1, 11, 35, 50, 35, 11, 1, 5, 35, 80, 80, 35, 5, 10, 50, 80, 50
Offset: 0

Views

Author

Philippe Deléham, Aug 26 2005

Keywords

Comments

Entries of slices [1,k] in A109672, read by rows.
Slice [n,0] gives A046816, slice [0,k] gives A109649, slice [n,n] gives A109673, slice [n,1] gives A109390.

Examples

			Slice [1,0]:
... 1 ...
.. 1 1 ...
Slice [1,1]:
... 1 1 ...
.. 1 3 1 ...
... 1 1 ...
Slice [1,2]:
... 1 2 1 ...
.. 1 5 5 1 ...
... 2 5 2 ...
.... 1 1 ....
Slice [1,3]:
... 1 3 3 1 ...
.. 1 7 12 7 1 ...
... 3 12 12 3 ...
.... 3 7 3 ....
..... 1 1 .....
Slice [1,4]:
... 1 4 6 4 1 ...
.. 1 9 22 22 9 1 ...
... 4 22 36 22 4 ...
.... 6 22 22 6 ....
..... 4 9 4 .....
...... 1 1 ......
Slice [1,5]:
... 1 5 10 10 5 1 ...
.. 1 11 35 50 35 11 1 ...
... 5 35 80 80 35 5 ...
.... 10 50 80 50 10 ....
..... 10 35 35 10 .....
...... 5 11 5 ......
....... 1 1
		

Crossrefs

Cf. A109390.

Formula

Sum of terms in 2D slice [1, k] is 3^(1+k).

A178819 Pascal's prism (3-dimensional array) read by folded antidiagonal cross-sections: (h+i; h, i-j, j), h >= 0, i >= 0, 0 <= j <= i.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 3, 3, 1, 3, 6, 3, 3, 3, 1, 1, 4, 4, 6, 12, 6, 4, 12, 12, 4, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1, 5, 20, 30, 20, 5, 10, 30, 30, 10, 10, 20, 10, 5, 5, 1, 1, 6, 6, 15, 30, 15, 20, 60, 60, 20, 15, 60, 90, 60, 15, 6, 30, 60, 60, 30, 6, 1, 6, 15, 20, 15, 6, 1
Offset: 0

Views

Author

Harlan J. Brothers, Jun 16 2010

Keywords

Comments

P_h = level h of Pascal's prism where P_1 = Pascal's triangle (A007318) and P_2 = denominators of Leibniz harmonic triangle (A003506). A sequence of length k through P is defined by P for n = {1, 2, 3, ..., k}.

Examples

			Prism begins (levels 1-4):
1
1 1
1 2 1
1 3 3 1
1
2 2
3 6 3
4 12 12 4
1
3 3
6 12 6
10 30 30 10
1
4 4
10 20 10
20 60 60 20
		

Crossrefs

Level 1 = A007318.
Level 2 = A003506.
Level 3 = A094305.
Level 4 = A178820.
Level 5 = A178821.
Level 6 = A178822.
Sums of shallow diagonals for each level correspond to rows of square A037027.
Contains A109649 and A046816.
P = A000984.
P = A006480.
P = A000897.
P<3n-2, 3n-2, n> = A113424.

Programs

  • Mathematica
    end = 5; Column/@Table[Multinomial[h, i-j, j], {h, 0, end}, {i, 0, end}, {j, 0, i}]

Formula

a_(h, i, j) = (h+i-2; h-1, i-j, j-1), h >= 1, i >= 1, 1 <= j <= i.
Recurrence:
For P_h, element a is given by: a_(1, 1) = 1; a_(i, j) = ((i+h-2)/(i-1)) (a_(i-1, j) + a_(i-1, j-1)).

Extensions

Keyword tabf by Michel Marcus, Oct 22 2017

A109495 Entries in 3-dimensional solid related to Prouhet-Tarry problem.

Original entry on oeis.org

1, 2, 2, 1, 2, 1, 1, 1, 2, 5, 2, 1, 5, 5, 1, 1, 2, 1, 1, 2, 1, 2, 8, 8, 2, 1, 8, 15, 8, 1, 2, 8, 8, 2, 1, 2, 1, 1, 3, 3, 1, 2, 11, 18, 11, 2, 1, 11, 31, 31, 11, 1, 3, 18, 31, 18, 3, 3, 11, 11, 3, 1, 2, 1, 1, 4, 6, 4, 1, 2, 14, 32, 32, 14, 2, 1, 14, 53, 80, 53, 14, 1, 4, 32, 80, 80, 32, 4, 6
Offset: 0

Views

Author

Philippe Deléham, Aug 29 2005

Keywords

Comments

Entries of slices [2,k] in A109672, read by rows.
Slice [n,0] gives A046816, slice [0,k] gives A109649, slice [n,n] gives A109673, slice [n,1] gives A109390, slice [1,k] gives A109393.

Examples

			Slice [2,0]:
.... 1 ....
... 2 2 ...
.. 1 2 1 ...
Slice [2,1]:
.... 1 1 ....
... 2 5 2 ...
.. 1 5 5 1 ...
... 1 2 1 ...
Slice [2,2]:
.... 1 2 1 ....
... 2 8 8 2 ...
.. 1 8 15 8 1 ...
... 2 8 8 2 ...
.... 1 2 1 ....
Slice [2,3]:
.... 1 3 3 1 ....
... 2 11 18 11 2 ...
.. 1 11 31 31 11 1 ...
... 3 18 31 18 3 ....
.... 3 11 11 3 .....
..... 1 2 1 ......
Slice [2,4]:
.... 1 4 6 4 1 ...
... 2 14 32 32 14 2 ...
.. 1 14 53 80 53 14 1 ...
... 4 32 80 80 32 4 ....
.... 6 32 53 32 6 .....
..... 4 14 14 4 .....;
...... 1 2 1 ......;
Slice [2,5]:
.... 1 5 10 10 5 1 ...
... 2 17 50 70 50 17 2 ...
.. 1 17 81 165 165 81 17 1 ...
... 5 50 165 240 165 50 5 ....
.... 10 70 165 165 70 10 .....
..... 10 50 81 50 10 ......
...... 5 17 17 5 ......
....... 1 2 1 .......
		

Crossrefs

Formula

Sum of terms in 2D slice [2, k] is 3^(2+k).

A344912 Irregular triangle read by rows, Trow(n) = Seq_{k=0..n/3} Seq_{j=0..n-3*k} (n! * binomial(n - 3*k, j)) / (k!*(n - 3*k)!*3^k).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 2, 1, 4, 6, 4, 1, 8, 8, 1, 5, 10, 10, 5, 1, 20, 40, 20, 1, 6, 15, 20, 15, 6, 1, 40, 120, 120, 40, 40, 1, 7, 21, 35, 35, 21, 7, 1, 70, 280, 420, 280, 70, 280, 280, 1, 8, 28, 56, 70, 56, 28, 8, 1, 112, 560, 1120, 1120, 560, 112, 1120, 2240, 1120
Offset: 0

Views

Author

Peter Luschny, Jun 04 2021

Keywords

Comments

Consider a sequence of Pascal tetrahedrons (depending on a parameter m >= 1), where the slices of the pyramid are scaled. They are given by the e.g.f.s exp(t^m / m) * exp(t*(x + y)), which provide a sequence of bivariate polynomials in x and y, whose monomials are to be ordered in degree-lexicographic order. For m = 1 one gets A109649 (resp. A046816), for m = 2 one gets A344911 (resp. A344678), and for m = 3 the current triangle. The row sums have an unexpected interpretation in A336614 (see the link).

Examples

			Triangle begins:
[0] 1;
[1] 1, 1;
[2] 1, 2,  1;
[3] 1, 3,  3,  1,  2;
[4] 1, 4,  6,  4,  1,  8,  8;
[5] 1, 5, 10, 10,  5,  1, 20, 40,  20;
[6] 1, 6, 15, 20, 15,  6,  1, 40, 120, 120,  40,  40;
[7] 1, 7, 21, 35, 35, 21,  7,  1,  70, 280, 420, 280, 70, 280, 280.
.
p_{6}(x, y) = x^6 + 6*x^5*y + 15*x^4*y^2 + 20*x^3*y^3 + 15*x^2*y^4 + 6*x*y^5 + y^6 + 40*x^3 + 120*x^2*y + 120*x*y^2 + 40*y^3 + 40.
		

Crossrefs

m=1: A109649, (A046816) [row sums A000244], scaling A007318 [row sums A000079].
m=2: A344911, (A344678) [row sums A005425], scaling A100861 [row sums A000085].
m=3: this triangle [row sums A336614], scaling A118931 [row sums A001470].

Programs

  • Maple
    B := (n, k) -> n!/(k!*(n - 3*k)!*(3^k)): C := n -> seq(binomial(n, j), j=0..n):
    T := (n, k) -> B(n, k)*C(n - 3*k): seq(seq(T(n, k), k = 0..n/3), n = 0..8);
  • Mathematica
    gf := Exp[t^3 / 3] Exp[t (x + y)]; ser := Series[gf, {t, 0, 9}];
    P[n_] := Expand[n! Coefficient[ser, t, n]];
    DegLexList[p_] := MonomialList[p, {x, y}, "DegreeLexicographic"] /. x->1 /. y->1;
    Table[DegLexList[P[n]], {n, 0, 7}] // Flatten

A109494 Entries in 3-dimensional solid related to Prouhet-Tarry problem.

Original entry on oeis.org

1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 5, 5, 1, 2, 5, 2, 1, 1, 1, 2, 1, 2, 8, 8, 1, 1, 8, 15, 8, 1, 2, 8, 8, 2, 1, 2, 1, 1, 2, 1, 3, 11, 11, 3, 3, 18, 31, 18, 3, 1, 11, 31, 31, 11, 1, 2, 11, 18, 11, 2, 1, 3, 3, 1, 1, 2, 1, 4, 14, 14, 4, 6, 32, 53, 32, 6, 4, 32, 80, 80, 32, 4, 1, 14, 53, 80, 53, 14, 1
Offset: 0

Views

Author

Philippe Deléham, Aug 29 2005

Keywords

Comments

Entries of slices [n,2] in A109672, read by rows.
Slice [n,0] gives A046816, slice [0,k] gives A109649, slice [n,n] gives A109673, slice [n,1] gives A109390, slice [1,k] gives A109393, slice [2,k] gives A109495.

Examples

			Slice [0,2]:
... 1 2 1 ...
.... 2 2 ....
..... 1 .....
Slice [1,2]:
... 1 2 1 ...
.. 1 5 5 1 ...
... 2 5 2 ...
.... 1 1 ....
Slice [2,2]:
.... 1 2 1 ....
... 2 8 8 2 ...
.. 1 8 15 8 1 ...
... 2 8 8 2 ...
.... 1 2 1 ....
Slice [3,2]:
..... 1 2 1 .....
.... 3 11 11 3 ....
... 3 18 31 18 3 ...
.. 1 11 31 31 11 1 ...
... 2 11 18 11 2 ...
.... 1 3 3 1 ....
Slice [4,2]:
...... 1 2 1 ......
..... 4 14 14 4 .....
.... 6 32 53 32 6 ....
... 4 32 80 80 32 4 ...
.. 1 14 53 80 53 14 1 ...
... 2 14 32 32 14 2 ...
.... 1 4 6 4 1 ....
Slice [5,2]:
....... 1 2 1 .......
...... 5 17 17 5 ......
..... 10 50 81 50 10 .....
.... 10 70 165 165 70 10 ....
... 5 50 165 240 165 50 5 ...
.. 1 17 81 165 165 81 17 1 ...
... 2 17 50 70 50 17 2 ...
.... 1 5 10 10 5 1 ....
		

Formula

Sum of terms in 2D slice [n, 2] is 3^(n+2).

A130046 Hexagonal pyramid of Pascal numbers in 3 dimensions. The 3-dimensional sequence is split into slices of the pyramid which in turn consist of rows of the slice, each containing multiple columns of numbers and where each element of slice j is composed of the sum of the three elements above it in slice j-1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 5, 2, 1, 5, 5, 1, 1, 2, 1, 1, 2, 1, 2, 8, 8, 2, 1, 8, 15, 8, 1, 2, 8, 8, 2, 1, 2, 1, 1, 2, 1, 3, 11, 11, 3, 3, 18, 31, 18, 3, 1, 11, 31, 31, 11, 1, 2, 11, 18, 11, 2, 1, 3, 3, 1, 1, 3, 3, 1, 3, 15, 24, 15, 3, 3, 24, 60, 60, 24, 3, 1, 15, 60, 93, 60, 15, 1, 3, 24
Offset: 0

Views

Author

Jeffrey C. Jacobs (darklord(AT)timehorse.com), May 03 2007

Keywords

Comments

Successive slices [0,0], [1,0], [1,1], [2,1], [2,2], [3,2], [3,3], [4,3], [4,4], ... in table A109672; see also A046816 (slices [n,0]), A109673 (slices [n,n]), A109649 (slices [0,k]), A109390 (slices [n,1]), A109393 (slices [1,k]), A109494 (slices [n,2]), A109495 (slices [2,k]). - Philippe Deléham, May 03 2007

Examples

			Slice[0]:
...
Slice[1]:
1
Slice[2]:
.1
1.1
Slice[3]:
.1.1
1.3.1
.1.1
Slice[4]:
..1.1
.2.5.2
1.5.5.1
.1.2.1
Slice[5]:
....1..2..1
..2..8..8..2
.1..8.15..8..1
..2..8..8..2
....1..2..1
Slice[6]:
.....1..2..1
....3.11.11..3
..3.18.31.18..3
.1.11.31.31.11..1
..2.11.18.11..2
....1..3..3..1
		

Crossrefs

Subsequence of A109672 table of slices.
Other tables of slices (see 2007 comment from Philippe Deléham): A046816, A109390, A109393, A109494, A109495, A109649, A109673.
Cf. A007318 (Pascal's triangle).

Formula

Let j be a given slice of the hexagonal pyramid. For j = 0, there are no elements.
For j > 0, let a[x] to a[x+y-1] represent the elements of the slice, where x is the (j-1)th element of A019298 and y is the j-th element of A077043. Each slice j consists of j rows of varying column length, numbered 0 to j-1.
The length of the first row of slice j is given by floor((j+1)/2) and the last row by floor(j/2)+1, where by convention the last row is always greater or equal in length to the first row.
The floor(j/2)th row is j columns in length and any row before it is given by the formula floor((j+1)/2) + row#. For rows after the floor(j/2)th row, the length is given by floor(j/2) + j - row#.
The elements a[x] to a[x+y-1] are thus layed out as a concatenated series of rows of varying column lengths as specified above.
Thus for a given slice j, the element at row row# and column col# is represented by a[x + floor((j+1)/2) * row# + row# * (row# - 1) / 2 + col# ] when row# <= floor(j/2) and by a[x + y - (floor(j/2) + 1) * (j - row#) - (j - row#) * (j - row# + 1) / 2 + col#] otherwise, where x and y are defined above and row# and col# start counting from 0.
The elements of a for a given slice j, row# and col#, represented by the coordinate pair (row#, col#), is given by the following recursive relation:
For j = 1, there is 1 element whose value is 1 at (0, 0). Call this Slice[1] whose first and only element forms a0 = 1.
For j > 1, each element (row#, col#) is given by the sum of the 3 elements above it in the pyramid. If the preceding slice does not contain one of the cells specified because the coordinates are invalid for that slice, the value is assumed to be 0.
The cells above can be found using the following formula for a given cell Slice[j](row#, col#):
If j is odd:
If row# > floor(j/2):
Sum:
Slice[j-1](row#, col#-1)
Slice[j-1](row#-1,col#)
Slice[j-1](row#-1,col#-1)
Otherwise:
Sum:
Slice[j-1](row#, col#)
Slice[j-1](row#-1,col#)
Slice[j-1](row#-1,col#-1)
Otherwise:
If row# > floor(j/2):
Sum:
Slice[j-1](row#, col#)
Slice[j-1](row#-1,col#)
Slice[j-1](row#,col#-1)
Otherwise:
Sum:
Slice[j-1](row#, col#)
Slice[j-1](row#,col#-1)
Slice[j-1](row#-1,col#-1)
Each slice is also a solution to the Prouhet-Tarry-Escott problem for a given n and k. The slices[n,k] in sequence A109672 map to the slices here by the relation k + n = j - 1, where k = n (j odd) or k = n + 1 (j even).
When j is even, k = n - 1 would also be a solution to the Pascal hexagonal pyramid, however here the k = n + 1 solution is chosen. For j even, the slices are also given by A109673.
Only 3 of the 6 hexagonal vertices have corresponding cells in the slice below them. Only every other vertex has a cell below it and all vertices with cells below them are always separated by 2 edges.
By convention, when constructing Slice[j] for j odd, the uppermost vertices of Slice[j-1] are chosen to have cells below them and for j even the 2 vertices adjacent to the uppermost vertices of Slice[j-1] are chosen.
Showing 1-8 of 8 results.