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.

Previous Showing 31-36 of 36 results.

A134141 Generalized unsigned Stirling1 triangle, S1p(7).

Original entry on oeis.org

1, 7, 1, 56, 21, 1, 504, 371, 42, 1, 5040, 6440, 1295, 70, 1, 55440, 114520, 36225, 3325, 105, 1, 665280, 2116800, 983920, 135975, 7105, 147, 1, 8648640, 40884480, 26714800, 5199145, 398860, 13426, 196, 1, 121080960, 826338240, 735469280
Offset: 1

Views

Author

Wolfdieter Lang, Oct 12 2007

Keywords

Comments

Signed lower triangular matrix (-1)^(n-m)*a(n,m) is inverse to matrix A092082(n, m) =: S2(7; n,m). The monic row polynomials E(n,x) := sum(a(n,m)*x^m, m=1..n), E(0,x) := 1 are exponential convolution polynomials (see A039692 for the definition and a Knuth reference).
a(n,m) enumerates unordered increasing n-vertex m-forests composed of m unary trees (out-degree r from {0,1}) whose vertices of depth (distance from the root) j>=1 come in j+6 colors. The k roots (j=0) each come in one (or no) color. - Wolfdieter Lang, Oct 05 2007
A triangle of numbers related to triangle A132166.
a(n,1)= A001730(n,5), n>=1. a(n,m)=: S1p(7; n,m), a member of a sequence of lower triangular Jabotinsky matrices with nonnegative entries, including S1p(1; n, m)= A008275 (unsigned Stirling first kind), S1p(2; n,m)= A008297(n, m) (unsigned Lah numbers). S1p(3; n,m)= A046089(n,m), S1p(4; n,m)= A049352, S1p(5; n,m)= A049353(n,m), S1p(6; n,m)= A049374(n, m).
The Bell transform of factorial(n+6)/factorial(6). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 18 2016

Examples

			{1}; {7,1}; {56,21,1}; {504,371,42,1}; ... E.g. Row polynomial E(3,x)=56*x+21*x^2+x^3.
a(4,2)= 371 = 4*(7*8)+3*(7*7) from the two types of unordered 2-forests of unary increasing trees associated with the two m=2 parts partitions (1,3) and (2^2) of n=4. The first type has 4 increasing labelings, each coming in (1)*(1*7*8)=56 colored versions, e.g., ((1c1),(2c1,3c7,4c5)) with lcp for vertex label l and color p. Here the vertex labeled 3 has depth j=1, hence 7 colors, c1..c7, can be chosen and the vertex labeled 4 with j=2 can come in 8 colors, e.g., c1..c8. Therefore there are 4*((1)*(1*7*8))=224 forests of this (1,3) type. Similarly the (2,2) type yields 3*((1*7)*(1*7))=147 such forests, e.g. ((1c1,3c4)(2c1,4c7)) or ((1c1,3c6)(2c1,4c2)), etc. - _Wolfdieter Lang_, Oct 05 2007
		

Crossrefs

First column A001730(n+5), n>=1.
Row sums A132164. Alternating row sums A132165.

Programs

Formula

a(n, m) = n!*A132166(n, m)/(m!*6^(n-m)); a(n, m) = (6*m+n-1)*a(n-1, m) + a(n-1, m-1), n >= m >= 1; a(n, m)=0, n

A048176 Generalized Stirling number triangle of first kind.

Original entry on oeis.org

1, -10, 1, 200, -30, 1, -6000, 1100, -60, 1, 240000, -50000, 3500, -100, 1, -12000000, 2740000, -225000, 8500, -150, 1, 720000000, -176400000, 16240000, -735000, 17500, -210, 1, -50400000000, 13068000000, -1313200000, 67690000, -1960000, 32200, -280, 1, 4032000000000, -1095840000000
Offset: 1

Keywords

Comments

a(n,m)= R_n^m(a=0,b=10) in the notation of the given reference.
a(n,m) is a Jabotinsky matrix, i.e., the monic row polynomials E(n,x) := sum(a(n,m)*x^m,m=1..n) = product(x-10*j,j=0..n-1), n >= 1, E(0,x) := 1, are exponential convolution polynomials (see A039692 for the definition and a Knuth reference).
Also the Bell transform of the sequence (-1)^n*A051262(n) without column 0. For the definition of the Bell transform see A264428. - Peter Luschny, Jan 28 2016

Examples

			{1}; {-10,1}; {200,-30,1}; {-6000,1100,-60,1}; ... E(3,x) = 200*x-30*x^2+x^3.
		

References

  • Mitrinovic, D. S.; Mitrinovic, R. S.; Tableaux d'une classe de nombres relies aux nombres de Stirling. Univ. Beograd. Pubi. Elektrotehn. Fak. Ser. Mat. Fiz. No. 77 1962, 77 pp.

Crossrefs

First (m=1) (unsigned) column sequence is: A051262(n-1). Row sums (signed triangle): A049212(n-1)*(-1)^(n-1). Row sums (unsigned triangle): A045757(n). b=8: A051187, b=9: A051231.

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1,0,0,0, ..) as column 0.
    BellMatrix(n -> (-1)^n*n!*10^n, 9); # Peter Luschny, Jan 28 2016
  • Mathematica
    rows = 9;
    t = Table[(-1)^n*n!*10^n, {n, 0, rows}];
    T[n_, k_] := BellY[n, k, t];
    Table[T[n, k], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 22 2018, after Peter Luschny *)

Formula

a(n, m) = a(n-1, m-1) - 10*(n-1)*a(n-1, m), n >= m >= 1; a(n, m) := 0, n

A049411 Triangle read by rows, the Bell transform of n!*binomial(5,n) (without column 0).

Original entry on oeis.org

1, 5, 1, 20, 15, 1, 60, 155, 30, 1, 120, 1300, 575, 50, 1, 120, 9220, 8775, 1525, 75, 1, 0, 55440, 114520, 36225, 3325, 105, 1, 0, 277200, 1315160, 730345, 112700, 6370, 140, 1, 0, 1108800, 13428800, 13000680, 3209745, 291060, 11130, 180, 1, 0, 3326400
Offset: 1

Keywords

Comments

Previous name was: A triangle of numbers related to triangle A049327.
a(n,1) = A008279(5,n-1). a(n,m) =: S1(-5; n,m), a member of a sequence of lower triangular Jabotinsky matrices, including S1(1; n,m) = A008275 (signed Stirling first kind), S1(2; n,m) = A008297(n,m) (signed Lah numbers). a(n,m) matrix is inverse to signed matrix ((-1)^(n-m))*A013988(n,m).
The monic row polynomials E(n,x) := sum(a(n,m)*x^m,m=1..n), E(0,x) := 1 are exponential convolution polynomials (see A039692 for the definition and a Knuth reference).
For the definition of the Bell transform see A264428 and the link. - Peter Luschny, Jan 16 2016

Examples

			Row polynomial E(3,x) = 20*x + 15*x^2 + x^3.
Triangle starts:
{  1}
{  5,    1}
{ 20,   15,   1}
{ 60,  155,  30,  1}
{120, 1300, 575, 50, 1}
		

Crossrefs

Cf. A049327.
Row sums give A049428.

Programs

  • Mathematica
    rows = 10;
    a[n_, m_] := BellY[n, m, Table[k! Binomial[5, k], {k, 0, rows}]];
    Table[a[n, m], {n, 1, rows}, {m, 1, n}] // Flatten (* Jean-François Alcover, Jun 22 2018 *)
  • Sage
    # uses[bell_matrix from A264428]
    # Adds 1,0,0,0,... as column 0 at the left side of the triangle.
    bell_matrix(lambda n: factorial(n)*binomial(5, n), 8) # Peter Luschny, Jan 16 2016

Formula

a(n, m) = n!*A049327(n, m)/(m!*6^(n-m));
a(n, m) = (6*m-n+1)*a(n-1, m) + a(n-1, m-1), n >= m >= 1;
a(n, m) = 0, n
E.g.f. for m-th column: (((-1+(1+x)^6)/6)^m)/m!.

Extensions

New name from Peter Luschny, Jan 16 2016

A049424 Triangle read by rows, the Bell transform of n!*binomial(4,n) (without column 0).

Original entry on oeis.org

1, 4, 1, 12, 12, 1, 24, 96, 24, 1, 24, 600, 360, 40, 1, 0, 3024, 4200, 960, 60, 1, 0, 12096, 40824, 17640, 2100, 84, 1, 0, 36288, 338688, 270144, 55440, 4032, 112, 1, 0, 72576, 2407104, 3580416, 1212624, 144144, 7056, 144, 1, 0, 72576, 14515200, 41791680
Offset: 1

Keywords

Comments

Previous name was: A triangle of numbers related to triangle A049326.
a(n,1) = A008279(4,n-1). a(n,m) =: S1(-4; n,m), a member of a sequence of lower triangular Jabotinsky matrices, including S1(1; n,m) = A008275 (signed Stirling first kind), S1(2; n,m) = A008297(n,m) (signed Lah numbers). a(n,m) matrix is inverse to signed matrix ((-1)^(n-m))*A011801(n,m). The monic row polynomials E(n,x) := Sum_{m=1..n} a(n,m)*x^m, E(0,x) := 1 are exponential convolution polynomials (see A039692 for the definition and a Knuth reference).
For the definition of the Bell transform see A264428 and the link. - Peter Luschny, Jan 16 2016

Examples

			E.g., row polynomial E(3,x) = 12*x + 12*x^2 + x^3.
Triangle starts:
   1;
   4,   1;
  12,  12,   1;
  24,  96,  24,   1;
  24, 600, 360,  40,   1;
		

Crossrefs

Cf. A049326.
Row sums give A049427.

Programs

  • Mathematica
    rows = 10;
    a[n_, m_] := BellY[n, m, Table[k! Binomial[4, k], {k, 0, rows}]];
    Table[a[n, m], {n, 1, rows}, {m, 1, n}] // Flatten (* Jean-François Alcover, Jun 22 2018 *)
  • Sage
    # uses[bell_matrix from A264428]
    # Adds 1, 0, 0, 0, ... as column 0 at the left side of the triangle.
    bell_matrix(lambda n: factorial(n)*binomial(2, n), 8) # Peter Luschny, Jan 16 2016

Formula

a(n, m) = n!*A049326(n, m)/(m!*5^(n-m));
a(n, m) = (5*m-n+1)*a(n-1, m) + a(n-1, m-1), n >= m >= 1;
a(n, m) = 0, n
E.g.f. for m-th column: (((-1+(1+x)^5)/5)^m)/m!.

Extensions

New name from Peter Luschny, Jan 16 2016

A051231 Generalized Stirling number triangle of the first kind.

Original entry on oeis.org

1, -9, 1, 162, -27, 1, -4374, 891, -54, 1, 157464, -36450, 2835, -90, 1, -7085880, 1797714, -164025, 6885, -135, 1, 382637520, -104162436, 10655064, -535815, 14175, -189, 1, -24106163760, 6944870988, -775431468, 44411409, -1428840, 26082, -252, 1
Offset: 1

Keywords

Comments

T(n,m) = R_n^m(a=0, b=9) in the notation of the given 1962 reference.
T(n,m) is a Jabotinsky matrix, i.e., the monic row polynomials E(n,x) := Sum_{m=1..n} T(n,m)*x^m = Product_{j=0..n-1} (x - 9*j), n >= 1, and E(0,x) := 1 are exponential convolution polynomials (see A039692 for the definition and a Knuth reference).
From Petros Hadjicostas, Jun 06 2020: (Start)
For nonnegative integers n, m and complex numbers a, b (with b <> 0), the numbers R_n^m(a,b) were introduced by Mitrinovic (1961) using slightly different notation. They were further examined by Mitrinovic and Mitrinovic (1962). Special cases were tabulated in this and other related papers.
Special cases of these numbers are related to numbers introduced by Nörlund (1924).
These numbers are defined via the g.f. Product_{r=0..n-1} (x - (a + b*r)) = Sum_{m=0..n} R_n^m(a,b)*x^m for n >= 0. As a result, R_n^m(a,b) = R_{n-1}^{m-1}(a,b) - (a + b*(n-1))*R_{n-1}^m(a,b) for n >= m >= 1 with R_1^0(a,b) = a, R_1^1(a,b) = 1, and R_n^m(a,b) = 0 for n < m. (Because an empty product is by definition 1, we may let R_0^0(a,b) = 1.)
With a = 0 and b = 1, we get the Stirling numbers of the first kind S1(n,m) = R_n^m(a=0, b=1) = A048994(n,m) which satisfy Product_{r=0}^{n-1} (x - r) = Sum_{m=0..n} S1(n,m)*x^m with S1(n,n) = 1 for n >= 0, S1(n,0) = 0 for n >= 1, and S1(n, m) = 0 for m > n. (Array A008275 is the same as array A048994 but with no zero row and no zero column.)
We have R_n^m(a,b) = Sum_{k=0}^{n-m} (-1)^k * a^k * b^(n-m-k) * binomial(m+k, k) * S1(n, m+k) for n >= m >= 0.
For the current array, T(n,m) = R_n^m(a=0, b=9) but with no zero row or column. (End)

Examples

			Triangle T(n,m) (with rows n >= 1 and columns m = 1..n) begins:
         1;
        -9,       1;
       162,     -27,       1;
     -4374,     891,     -54,    1;
    157464,  -36450,    2835,  -90,    1;
  -7085880, 1797714, -164025, 6885, -135, 1;
   ...
3rd row o.g.f.: E(3,x) = Product_{j=0..2} (x-9*j) = 162*x - 27*x^2 + x^3. [Edited by _Petros Hadjicostas_, Jun 06 2020]
		

Crossrefs

First (m=1) column sequence is A051232(n-1).
Row sums (signed triangle): A049211(n-1)*(-1)^(n-1).
Row sums (unsigned triangle): A045756(n).
Cf. A008275 (b=1 triangle), A048994 (b=1 triangle), A051187 (b=8 triangle).

Formula

T(n, m) = T(n-1, m-1) - 9*(n-1)*T(n-1, m), n >= m >= 1; T(n, m) := 0, n < m; T(n, 0) := 0 for n >= 1; T(0, 0) = 1.
E.g.f. for the m-th column of the signed triangle: (log(1 + 9*x)/9)^m/m!.
From Petros Hadjicostas, Jun 07 2020: (Start)
T(n,m) = 9^(n-m)*Stirling1(n,m) = 9^(n-m)*A048994(n,m) = 9^(n-m)*A008275(n,m) for n >= m >= 1.
Bivariate e.g.f.-o.g.f.: Sum_{n,m >= 1} T(n,m)*x^n*y^m/n! = exp((y/9)*log(1 + 9*x)) - 1 = (1 + 9*x)^(y/9) - 1. (End)

A194938 Triangle read by rows: coefficients of polynomials p(x,n) defined by 1/(1-t-t^2)^x = Sum_{n=1..oo} p(x,n)*t^n/n!.

Original entry on oeis.org

1, 0, 1, 0, 3, 1, 0, 8, 9, 1, 0, 42, 59, 18, 1, 0, 264, 450, 215, 30, 1, 0, 2160, 4114, 2475, 565, 45, 1, 0, 20880, 43512, 30814, 9345, 1225, 63, 1, 0, 236880, 528492, 420756, 154609, 27720, 2338, 84, 1, 0, 3064320, 7235568, 6316316, 2673972, 594489, 69552
Offset: 1

Author

Roger L. Bagula, Apr 17 2008

Keywords

Comments

A039692 is a similar triangle but without the leading column.
1/(1-t-t^2) is the g.f. for the Fibonacci numbers (A000045).
Row sums: A005442(n-1).
Also the Bell transform of n!*(F(n)+F(n+2)), F(n) the Fibonacci numbers. For the definition of the Bell transform see A264428. - Peter Luschny, Jan 21 2016

Examples

			Triangle begins
1;
0, 1;
0, 3, 1;
0, 8, 9, 1;
0, 42, 59, 18, 1;
0, 264, 450, 215, 30, 1;
0, 2160, 4114, 2475, 565, 45, 1;
0, 20880, 43512, 30814, 9345, 1225, 63, 1;
0, 236880, 528492, 420756, 154609, 27720, 2338, 84, 1;
0, 3064320, 7235568, 6316316, 2673972, 594489, 69552, 4074, 108, 1;
0, 44634240, 110499696, 103889700, 49087520, 12803175, 1887753, 154350,6630,135,1;
		

References

  • Steve Roman, The Umbral Calculus, Dover Publications, New York (1984), pp. 149-150

Crossrefs

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    with(combinat): g := n -> factorial(n)*(fibonacci(n)+fibonacci(n+2)):
    BellMatrix(g, 10); # Peter Luschny, Jan 21 2016
  • Mathematica
    p[t_] = 1/(1 - t - t^2)^x; Table[ ExpandAll[n!SeriesCoefficient[ Series[p[t], {t, 0, 30}], n]], {n, 0, 10}]; a = Table[n!* CoefficientList[SeriesCoefficient[ Series[p[t], {t, 0, 30}], n], x], {n, 0, 10}]; Flatten[a]
    (* Second program *)
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    B = BellMatrix[Function[n, n!*(Fibonacci[n] + Fibonacci[n+2])], rows = 12];
    Table[B[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny *)
  • Sage
    # uses[bell_matrix from A264428]
    bell_matrix(lambda n: factorial(n)*(fibonacci(n)+fibonacci(n+2)), 8) # Peter Luschny, Jan 21 2016

Extensions

Edited by N. J. A. Sloane, Aug 28 2011
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