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.

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A089517 Array used for numerators of g.f.s for column sequences of array A078741 ((3,3)-Stirling2).

Original entry on oeis.org

1, 18, 9, 432, 1, 672, 14400, 243, 47520, 648000, 27, 36396, 3790800, 38102400, 1, 9765, 5115888, 354715200, 2844979200, 1107, 2499552, 757646784, 39182330880, 263363788800, 54, 546453, 592216272, 123294623040, 5089348454400
Offset: 3

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Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

The row length sequence for this array is A004396(n-2)=floor((2*n-3)/3), n>=3: [1,1,2,3,3,4,5,5,6,7,7,8,9,9,10,...].
The g.f. G(m,x) for the m-th column sequence (with leading zeros) of array A078741 is given there. The recurrence is G(m,x) = x*(3*fallfac(m-1,2)*G(m-1,x) + 3*(m-2)*G(m-2,x) + G(m-3,x))/(1-fallfac(m,3)*x), m>=4, with inputs G(1,x)=0=G(2,x) and G(3,x)=x/(1-(3*2*1)*x); where fallfac(n,m) := A008279(n,m) (falling factorials). Computed from the Blasiak et al. reference, eqs. (20) and (21) with r=3: recurrence for S_{3,3}(n,k).

Examples

			[1]; [18]; [9,423]; [1,672,14400]; [243,47520,648000]; ...
G(4,x)/(x^2) = 18/((1-3*2*1*x)*(1-4*3*2*x)). kmax(4)=0, hence P(4,x)=a(4,0)=18; x^2 from x^ceiling(4/3).
		

Formula

a(n, m) from: sum(a(n, m)*x^m, m=0..kmax(n)) = G(n, x)* product(1-fallfac(p, 3)*x, p=3..n)/x^ceiling(n/3), n>=3, with G(n, x) defined from the recurrence given above and kmax(n) := A004523(n-3)= floor(2*(n-3)/3) = A004396(n-3)-1.

A090217 A generalization of triangle A071951 (Legendre-Stirling).

Original entry on oeis.org

1, 120, 1, 14400, 840, 1, 1728000, 619200, 3360, 1, 207360000, 447552000, 9086400, 10080, 1, 24883200000, 322444800000, 23345280000, 76824000, 25200, 1, 2985984000000, 232185139200000, 59152550400000, 539602560000, 457848000
Offset: 1

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

This is the fourth member of the family A071951 (Legendre-Stirling,(2,2) case), A089504((3,3)-case), A090215 ((4,4)-case).
This triangle underlies the array entry A090216 ((5,5)-generalized Stirling2).

Examples

			Triangle starts:
[1];
[120,1];
[14400,840,1];
[1728000,619200,3360,1];
...
		

Crossrefs

The column sequences (without leading zeros) are powers of 120, etc.

Programs

  • Mathematica
    max = 10; f[m_] := 1/Product[1 - FactorialPower[r + 4, 5]*x, {r, 1, m}]; col[m_] := CoefficientList[f[m] + O[x]^(max - m + 1), x]; a[n_, m_] := col[m][[n - m + 1]]; Table[a[n, m], {n, 1, max}, {m, 1, n}] // Flatten (* Jean-François Alcover, Sep 02 2016 *)

Formula

G.f. for m-th column (without leading zeros and m>=1) is 1/product(1-fallfac(r+4, 5)*x, r=1..m) with fallfac(n, k) := A008279(n, k) (falling factorials).
a(n, m)=sum(A090435(m, p)*fallfac(p, 5)^(n-m), p=1..m)/D(m) if n>=m>=1 else 0; with D(m) := A090436(m).

A122851 Number triangle T(n,k) = C(k,n-k)*(n-k)!.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 0, 2, 1, 0, 0, 2, 3, 1, 0, 0, 0, 6, 4, 1, 0, 0, 0, 6, 12, 5, 1, 0, 0, 0, 0, 24, 20, 6, 1, 0, 0, 0, 0, 24, 60, 30, 7, 1, 0, 0, 0, 0, 0, 120, 120, 42, 8, 1, 0, 0, 0, 0, 0, 120, 360, 210, 56, 9, 1, 0, 0, 0, 0, 0, 0, 720, 840, 336, 72, 10, 1
Offset: 0

Views

Author

Paul Barry, Sep 14 2006

Keywords

Comments

Row sums are A122852.
Triangle T(n,k), read by rows, given by (0,1,-1,0,0,1,-1,0,0,1,-1,0,0,1,...) DELTA (1,0,0,-1,2,0,0,-2,3,0,0,-3,4,...) where DELTA is the operator defined in A084938. - Philippe Deléham, Dec 12 2011

Examples

			Triangle begins
  1;
  0, 1;
  0, 1, 1;
  0, 0, 2, 1;
  0, 0, 2, 3,  1;
  0, 0, 0, 6,  4,  1;
  0, 0, 0, 6, 12,  5, 1;
  0, 0, 0, 0, 24, 20, 6, 1;
  ...
		

Crossrefs

T(2n,n) gives A000142.

Programs

  • Magma
    /* As triangle: */ [[Binomial(k,n-k)*Factorial(n-k): k in [0..n]]: n in [0.. 7]]; // Vincenzo Librandi, Apr 24 2015
  • Mathematica
    Flatten[Table[Binomial[k,n-k](n-k)!,{n,0,10},{k,0,n}]] (* Harvey P. Dale, May 16 2012 *)

Formula

Number triangle T(n,k) = [k<=n]*k!/(2k-n)!.
T(n,k) = A008279(k,n-k). - Danny Rorabaugh, Apr 23 2015

A144357 Partition number array, called M31(-1), related to A049403(n,m) = S1(-1;n,m) (generalized Stirling triangle).

Original entry on oeis.org

1, 1, 1, 0, 3, 1, 0, 0, 3, 6, 1, 0, 0, 0, 0, 15, 10, 1, 0, 0, 0, 0, 0, 0, 15, 0, 45, 15, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 105, 0, 105, 21, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 105, 0, 0, 420, 0, 210, 28, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 945, 0, 0, 1260, 0, 378, 36
Offset: 1

Views

Author

Wolfdieter Lang, Oct 09 2008, Oct 28 2008

Keywords

Comments

Each partition of n, ordered as in Abramowitz-Stegun (A-St order; for the reference see A134278), is mapped to a nonnegative integer a(n,k) =: M31(-1;n,k) with the k-th partition of n in A-St order.
The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42, ...].
First member (K=1) in the family M31(-K) of partition number arrays.
If M31(-1;n,k) is summed over those k with fixed number of parts m one obtains the unsigned triangle S1(-1) := A049403.

Examples

			[1]; [1,1]; [0,3,1]; [0,0,3,6,1]; [0,0,0,0,15,10,1]; ...
a(4,3) = 3 = 3*S1(-1;2,1)^2. The relevant partition of 4 is (2^2).
		

Crossrefs

Cf. A000085 (row sums).
Cf. A144358 (M31(-2) array).

Formula

a(n,k) = (n!/(Product_{j=1..n} e(n,k,j)!*j!^e(n,k,j))*Product_{j=1..n} S1(-1;j,1)^e(n,k,j) = M3(n,k)*Product_{j=1..n} S1(-1;j,1)^e(n,k,j) with S1(-1;n,1) |= A008279(1,n-1) = [1,1,0,...], n >= 1 and the exponent e(n,k,j) of j in the k-th partition of n in the A-St ordering of the partitions of n. M3(n,k) = A036040.

A144879 Partition number array, called M31(-5), related to A049411(n,m) = S1(-5;n,m) (generalized Stirling triangle).

Original entry on oeis.org

1, 5, 1, 20, 15, 1, 60, 80, 75, 30, 1, 120, 300, 1000, 200, 375, 50, 1, 120, 720, 4500, 4000, 900, 6000, 1875, 400, 1125, 75, 1, 0, 840, 12600, 42000, 2520, 31500, 28000, 52500, 2100, 21000, 13125, 700, 2625, 105, 1, 0, 0, 16800, 134400, 126000, 3360, 100800, 336000
Offset: 1

Views

Author

Wolfdieter Lang Oct 09 2008, Oct 28 2008

Keywords

Comments

Each partition of n, ordered as in Abramowitz-Stegun (A-St order; for the reference see A134278), is mapped to a nonnegative integer a(n,k) =: M31(-5;n,k) with the k-th partition of n in A-St order.
The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42, ...].
First member (K=5) in the family M31(-K) of partition number arrays.
If M31(-5;n,k) is summed over those k with fixed number of parts m one obtains the unsigned triangle S1(-5) := A049411.

Examples

			[1]; [5,1]; [20,15,1]; [60,80,75,30,1]; [120,300,1000,200,375,50,1]; ...
a(4,3) = 75 = 3*S1(-5;2,1)^2. The relevant partition of 4 is (2^2).
		

Crossrefs

Cf. A049428 (row sums).
Cf. A144878 (M31(-4) array).

Formula

a(n,k)=(n!/Product_{j=1..n} (e(n,k,j)!*j!^e(n,k,j))) * Product_{j=1..n} S1(-5;j,1)^e(n,k,j) = M3(n,k) * Product_{j=1..n} S1(-5;j,1)^e(n,k,j), with S1(-5;n,1) = A008279(5,n-1)= [1,5,20,60,120,120,0,...], n>=1 and the exponent e(n,k,j) of j in the k-th partition of n in the A-St ordering of the partitions of n. M3(n,k)=A036040.

A145364 Lower triangular array, called S1hat(-2), related to partition number array A145363.

Original entry on oeis.org

1, 2, 1, 2, 2, 1, 0, 6, 2, 1, 0, 4, 6, 2, 1, 0, 4, 12, 6, 2, 1, 0, 0, 12, 12, 6, 2, 1, 0, 0, 8, 28, 12, 6, 2, 1, 0, 0, 8, 24, 28, 12, 6, 2, 1, 0, 0, 0, 24, 56, 28, 12, 6, 2, 1, 0, 0, 0, 16, 56, 56, 28, 12, 6, 2, 1, 0, 0, 0, 16, 48, 120, 56, 28, 12, 6, 2, 1, 0, 0, 0, 0, 48, 112, 120, 56, 28, 12, 6, 2, 1
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If in the partition array M31hat(-2):=A145363 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-2). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.
The first column is [1,2,2,0,0,0,...]= A008279(2,n-1), n>=1.

Examples

			Triangle begins:
  [1];
  [2,1];
  [2,2,1];
  [0,6,2,1];
  [0,4,6,2,1];
  ...
		

Crossrefs

Cf. A145365 (row sums).

Formula

a(n,m) = sum(product(S1(-2;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-2,n,1)= A008279(2,n-1) = [1,2,2,0,0,0,...], n>=1.

A145367 Lower triangular array, called S1hat(-3), related to partition number array A145366.

Original entry on oeis.org

1, 3, 1, 6, 3, 1, 6, 15, 3, 1, 0, 24, 15, 3, 1, 0, 54, 51, 15, 3, 1, 0, 36, 108, 51, 15, 3, 1, 0, 36, 198, 189, 51, 15, 3, 1, 0, 0, 360, 360, 189, 51, 15, 3, 1, 0, 0, 324, 846, 603, 189, 51, 15, 3, 1, 0, 0, 216, 1296, 1332, 603, 189, 51, 15, 3, 1, 0, 0, 216, 2484, 2754, 2061, 603, 189
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If in the partition array M31hat(-3):=A145366 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-3). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.
The first column is [1,3,6,6,0,0,0,...]= A008279(3,n-1), n>=1.

Examples

			Triangle begins:
  [1];
  [3,1];
  [6,3,1];
  [6,15,3,1];
  [0,24,15,3,1];
  ...
		

Crossrefs

Cf. A145368 (row sums).

Formula

a(n,m) = sum(product(S1(-3;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-3,n,1)= A008279(3,n-1) = [1,3,6,6,0,0,0,...], n>=1.

A145369 Partition number array, called M31hat(-4).

Original entry on oeis.org

1, 4, 1, 12, 4, 1, 24, 12, 16, 4, 1, 24, 24, 48, 12, 16, 4, 1, 0, 24, 96, 144, 24, 48, 64, 12, 16, 4, 1, 0, 0, 96, 288, 24, 96, 144, 192, 24, 48, 64, 12, 16, 4, 1, 0, 0, 0, 288, 576, 0, 96, 288, 384, 576, 24, 96, 144, 192, 256, 24, 48, 64, 12, 16, 4, 1, 0, 0, 0, 0, 576, 0, 0, 288, 576, 384
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If all positive numbers are replaced by 1 this becomes the characteristic partition array for partitions with parts 1,2,3,4 or 5 only, provided the partitions of n are ordered like in Abramowitz-Stegun (A-St order; for the reference see A134278).
Fourth member (K=4) in the family M31hat(-K) of partition number arrays.
The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42,...].
This array is array A144878 divided entrywise by the array M_3=M3(1)=A036040. Formally 'A144878/A036040'. E.g. a(4,3)= 16 = 48/3 = A144878(4,3)/A036040(4,3).
If M31hat(-4;n,k) is summed over those k numerating partitions with fixed number of parts m one obtains the unsigned triangle S1hat(-4):= A145370.

Examples

			Triangle begins:
  [1];
  [4,1];
  [12,4,1];
  [24,12,16,4,1];
  [24,24,48,12,16,4,1];
  ...
a(4,3)= 16 = S1(-4;2,1)^2. The relevant partition of 4 is (2^2).
		

Crossrefs

Cf. A145366 (M31hat(-3)), A145372 (M31hat(-5)).

Formula

a(n,k) = product(S1(-4;j,1)^e(n,k,j),j=1..n) with S1(-4;n,1) = A008279(4,n-1) = [1,4,12,24,24,0,0,0,...], n>=1 and the exponent e(n,k,j) of j in the k-th partition of n in the A-St ordering of the partitions of n.

A145370 Lower triangular array, called S1hat(-4), related to partition number array A145369.

Original entry on oeis.org

1, 4, 1, 12, 4, 1, 24, 28, 4, 1, 24, 72, 28, 4, 1, 0, 264, 136, 28, 4, 1, 0, 384, 456, 136, 28, 4, 1, 0, 864, 1344, 712, 136, 28, 4, 1, 0, 576, 4128, 2112, 712, 136, 28, 4, 1, 0, 576, 7488, 7968, 3136, 712, 136, 28, 4, 1, 0, 0, 13248, 20544, 11040, 3136, 712, 136, 28, 4, 1, 0, 0
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If in the partition array M31hat(-4):=A145369 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-4). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.
The first column is [1,4,12,24,24,0,0,0,...]= A008279(4,n-1), n>=1.

Examples

			Triangle begins:
  [1];
  [4,1];
  [12,4,1];
  [24,28,4,1];
  [24,72,28,4,1];
  ...
		

Crossrefs

Cf. A145371 (row sums).

Formula

a(n,m) = sum(product(S1(-4;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n, Y and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-4,n,1)= A008279(4,n-1) = [1,4,12,24,24,0,0,0,...], n>=1.

A145372 Partition number array, called M31hat(-5).

Original entry on oeis.org

1, 5, 1, 20, 5, 1, 60, 20, 25, 5, 1, 120, 60, 100, 20, 25, 5, 1, 120, 120, 300, 400, 60, 100, 125, 20, 25, 5, 1, 0, 120, 600, 1200, 120, 300, 400, 500, 60, 100, 125, 20, 25, 5, 1, 0, 0, 600, 2400, 3600, 120, 600, 1200, 1500, 2000, 120, 300, 400, 500, 625, 60, 100, 125, 20
Offset: 1

Views

Author

Wolfdieter Lang, Oct 17 2008

Keywords

Comments

If all positive numbers are replaced by 1 this becomes the characteristic partition array for partitions with parts 1,2,3,4,5 or 6 only, provided the partitions of n are ordered like in Abramowitz-Stegun (A-St order; for the reference see A134278).
Fifth member (K=5) in the family M31hat(-K) of partition number arrays.
The sequence of row lengths is A000041 (partition numbers) [1, 2, 3, 5, 7, 11, 15, 22, 30, 42,...].
This array is array A144879 divided entrywise by the array M_3=M3(1)=A036040. Formally 'A144879/A036040'. E.g. a(4,3)= 25 = 75/3 = A144879(4,3)/A036040(4,3).
If M31hat(-5;n,k) is summed over those k numerating partitions with fixed number of parts m one obtains the unsigned triangle S1hat(-5):= A145373.

Examples

			Triangle begins;
  [1];
  [5,1];
  [20,5,1];
  [60,20,25,5,1];
  [120,60,100,20,25,5,1];
  ...
a(4,3)= 25 = S1(-4;2,1)^2. The relevant partition of 4 is (2^2).
		

Crossrefs

Cf. A145369 (M31hat(-4)).

Formula

a(n,k) = product(S1(-5;j,1)^e(n,k,j),j=1..n) with S1(-5;n,1) = A008279(5,n-1) = [1,5,20,60,120,120,0,0,0,...], n>=1 and the exponent e(n,k,j) of j in the k-th partition of n in the A-St ordering of the partitions of n.
Previous Showing 61-70 of 117 results. Next