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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A062138 Coefficient triangle of generalized Laguerre polynomials n!*L(n,5,x)(rising powers of x).

Original entry on oeis.org

1, 6, -1, 42, -14, 1, 336, -168, 24, -1, 3024, -2016, 432, -36, 1, 30240, -25200, 7200, -900, 50, -1, 332640, -332640, 118800, -19800, 1650, -66, 1, 3991680, -4656960, 1995840, -415800, 46200, -2772, 84, -1, 51891840, -69189120
Offset: 0

Views

Author

Wolfdieter Lang, Jun 19 2001

Keywords

Comments

The row polynomials s(n,x) := n!*L(n,5,x)= sum(a(n,m)*x^m,m=0..n) have e.g.f. exp(-z*x/(1-z))/(1-z)^6. They are Sheffer polynomials satisfying the binomial convolution identity s(n,x+y) = sum(binomial(n,k)*s(k,x)*p(n-k,y),k=0..n), with polynomials sum(|A008297(n,m)|*(-x)^m, m=1..n), n >= 1 and p(0,x)=1 (for Sheffer polynomials see A048854 for S. Roman reference).
These polynomials appear in the radial part of the l=2 (d-wave) eigen functions for the discrete energy levels of the H-atom. See Messiah reference.
For m=0..5 the (unsigned) column sequences (without leading zeros) are: A001725(n+5), A062148-A062152. Row sums (signed) give A062191; row sums (unsigned) give A062192.
The unsigned version of this triangle is the triangle of unsigned 3-Lah numbers A143498. - Peter Bala, Aug 25 2008

Examples

			Triangle begins:
  {1};
  {6, -1};
  {42, -14, 1};
  {336, -168, 24, -1};
  ...
2!*L(2, 5, x) = 42-14*x+x^2.
		

References

  • A. Messiah, Quantum mechanics, vol. 1, p. 419, eq.(XI.18a), North Holland, 1969.

Crossrefs

For m=0..5 the (unsigned) column sequences (without leading zeros) are: A001725(n+5), A062148, A062149, A062150, A062151, A062152.
Row sums (signed) give A062191, row sums (unsigned) give A062192.
Cf. A143498.

Programs

  • Mathematica
    Flatten[Table[((-1)^m)*n!*Binomial[n+5,n-m]/m!,{n,0,8},{m,0,n}]] (* Indranil Ghosh, Feb 24 2017 *)
  • PARI
    tabl(nn) = {for (n=0, nn, for (m=0, n, print1(((-1)^m)*n!*binomial(n+5, n-m)/m!, ", "); ); print(); ); } \\ Indranil Ghosh, Feb 24 2017
    
  • PARI
    row(n) = Vecrev(n!*pollaguerre(n, 5)); \\ Michel Marcus, Feb 06 2021
    
  • Python
    import math
    f=math.factorial
    def C(n, r):return f(n)//f(r)//f(n-r)
    i=-1
    for n in range(26):
        for m in range(n+1):
            i += 1
            print(str(i)+" "+str(((-1)**m)*f(n)*C(n+5, n-m)//f(m))) # Indranil Ghosh, Feb 24 2017

Formula

T(n, m) = ((-1)^m)*n!*binomial(n+5, n-m)/m!.
E.g.f. for m-th column: ((-x/(1-x))^m)/(m!*(1-x)^6), m >= 0.

A123202 Triangle of coefficients of n!*(1 - x)^n*L_n(x/(1 - x)), where L_n(x) is the Laguerre polynomial.

Original entry on oeis.org

1, 1, -2, 2, -8, 7, 6, -36, 63, -34, 24, -192, 504, -544, 209, 120, -1200, 4200, -6800, 5225, -1546, 720, -8640, 37800, -81600, 94050, -55656, 13327, 5040, -70560, 370440, -999600, 1536150, -1363572, 653023, -130922, 40320, -645120, 3951360, -12794880
Offset: 0

Views

Author

Roger L. Bagula, Oct 04 2006

Keywords

Comments

The n-th row consists of the coefficients in the expansion of Sum_{j=0..n} A021009(n,j)*x^j*(1 - x)^(n - j).

Examples

			Triangle begins:
       1;
       1,    -2;
       2,    -8,     7;
       6,   -36,    63,    -34;
      24,  -192,   504,   -544,   209;
     120, -1200,  4200,  -6800,  5225,  -1546;
     720, -8640, 37800, -81600, 94050, -55656, 13327;
      ... reformatted. - _Franck Maminirina Ramaharo_, Oct 13 2018
		

References

  • Milton Abramowitz and Irene A. Stegun, eds., Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables, 9th printing. New York: Dover, 1972, p. 782.
  • Gengzhe Chang and Thomas W. Sederberg, Over and Over Again, The Mathematical Association of America, 1997, p. 164, figure 26.1.

Crossrefs

Programs

  • Maple
    M := (n,x) -> n!*subs(x=(x/(1-x)),orthopoly[L](n,x))*(1-x)^n:
    seq(print(seq(coeff(simplify(M(n,x)),x,k),k=0..n)),n=0..6); # Peter Luschny, Jan 05 2015
  • Mathematica
    w = Table[n!*CoefficientList[LaguerreL[n, x], x], {n, 0, 10}];
    v = Table[CoefficientList[Sum[w[[n + 1]][[m + 1]]*x^ m*(1 - x)^(n - m), {m, 0, n}], x], {n, 0, 10}]; Flatten[v]
  • Maxima
    create_list(ratcoef(n!*(1 - x)^n*laguerre(n, x/(1 - x)), x, k), n, 0, 10, k, 0, n); /* Franck Maminirina Ramaharo, Oct 13 2018 */
    
  • PARI
    row(n) = Vecrev(n!*(1-x)^n*pollaguerre(n, 0, x/(1 - x))); \\ Michel Marcus, Feb 06 2021

Formula

T(n, k) = [x^k] (n!*L_n(x)*(1 - x)^n) with L_n(x) the Laguerre polynomial after substituting x by x/(1 - x). - Peter Luschny, Jan 05 2015
From Franck Maminirina Ramaharo, Oct 13 2018: (Start)
G.f.: exp(-x*y/(1 - (1 - x)*y))/(1 - (1 - x)*y).
T(n,1) = A000142(n).
T(n,2) = -A052582(n).
T(n,n) = A002720(n). (End)

Extensions

Edited by N. J. A. Sloane, Jun 12 2007
Edited, new name, and offset corrected by Franck Maminirina Ramaharo, Oct 13 2018

A130757 Triangular table of coefficients of Laguerre-Sonin polynomials n!*2^n*Lag(n,x/2,1/2) of order 1/2.

Original entry on oeis.org

1, 3, -1, 15, -10, 1, 105, -105, 21, -1, 945, -1260, 378, -36, 1, 10395, -17325, 6930, -990, 55, -1, 135135, -270270, 135135, -25740, 2145, -78, 1, 2027025, -4729725, 2837835, -675675, 75075, -4095, 105, -1, 34459425, -91891800, 64324260, -18378360, 2552550, -185640, 7140, -136
Offset: 0

Views

Author

Wolfdieter Lang, Jul 13 2007

Keywords

Comments

These polynomials appear in the radial l=0 (s) wave functions of the isotropic three-dimensional harmonic quantum oscillator with the dimensionless variable x=(r/L)^2 with r>=0 and L^2=h/(m*f0). h is Planck's constant and m and f0 are the mass and the frequency of the oscillator.
From Tom Copeland, Dec 13 2015: (Start)
See A099174 for relations to the Hermite polynomials and the link in A176230 for operator relations. The infinitesimal generator for this matrix contains A014105.
The row polynomials are P(n,x) = 2^n n! Lag(n,x/2,1/2), where Lag(n,x,q) is the associated Laguerre polynomial of order q, with raising operator R = -x^(-2) [x^(3/2) (1 - 2D)]^2 = 3 - x + (4x - 6) D - 4x D^2 with D = d/dx, i.e., R P(n,x) - P(n+1,x). A matrix reresentation of R acting on an o.g.f. (formal power series) is given by the transpose of the production matrix below. The diagonal corresponds to (3 + 4 xD) x^n = (3 + 4n) x^n; the upper diagonal, to -x x^n = -x^(n+1); and the lower diagonal, to (-6 - 4 xD) D x^n = -n (6 + 4(n-1)) x^(n-1), the sequence A002943. See A176230 for a similar relation.
The triangles of Bessel numbers entries A122848, A049403, A096713, A104556 contain these polynomials as even or odd rows. Also the aerated version A099174 and A066325. Reversed, these entries are A100861, A144299, A111924.
(End)
Exponential Riordan array [1/(1-2x)^(3/2), -x/(1-2x)]. - Paul Barry, Mar 07 2017

Examples

			[1]; [3,-1]; [15,-10,1]; [105,-105,21,-1]; [945,-1260,378,-36,1]; ...
		

Crossrefs

Cf. A021009 (Coefficient table of n!*L(n, 0, x)).
Row sums (signed) give A131441. Row sums (unsigned) give A066224.

Programs

  • Maple
    seq(seq(n!*2^(n-m)*(-1)^m*binomial(n+1/2,n-m)/m!,m=0..n),n=0..10); # Robert Israel, Dec 25 2015
  • Mathematica
    Table[n! (2^(n - m)) ((-1)^m) Binomial[n + 1/2, n - m]/m!, {n, 0, 8}, {m, 0, n}] // Flatten (* Michael De Vlieger, Dec 24 2015 *)

Formula

a(n,m) = n!*(2^(n-m))*L(1/2,n,m) with L(1/2,n,m) = ((-1)^m)*binomial(n+1/2,n-m)/m!, n >= m >= 0, otherwise 0.
Let IP be the lower triangular matrix with its first subdiagonal equal to the first subdiagonal (cf. A014105) of this entry's unsigned matrix M and with all other elements equal to zero. Then IP is the infinitesimal generator of M, i.e., M = exp(IP). - Tom Copeland, Dec 12 2015
From Tom Copeland, Dec 14 2015: (Start)
Production matrix is
3, -1;
-6, 7, -1;
0, -20, 11, -1;
0, 0, -42, 15, -1;
0, 0, 0, -72, 19, -1;
0, 0, 0, 0, -110, 23, -1;
0, 0, 0, 0, 0, -156, 27, -1;
0, 0, 0, 0, 0, 0, -210, 31, -1;
0, 0, 0, 0, 0, 0, 0, -272, 35, -1;
... (End)

Extensions

Title formula corrected by Tom Copeland, Dec 12 2015

A025167 E.g.f: exp(x/(1-2*x))/(1-2*x).

Original entry on oeis.org

1, 3, 17, 139, 1473, 19091, 291793, 5129307, 101817089, 2250495523, 54780588561, 1455367098923, 41888448785857, 1298019439099059, 43074477771208913, 1523746948247663611, 57229027745514785793, 2274027983943883110467
Offset: 0

Views

Author

Keywords

Comments

Polynomials in A021009 evaluated at -2.
Also, a(n) is the number of signed permutations of length 2n that are equal to their reverse-complements and avoid the pattern (-2,-1). As a result, a(n) also gives the same thing but for avoiding any one of (-1,-2), (+2,+1) or (+1,+2) instead of (-2,-1) (see the Hardt and Troyka reference). - Justin M. Troyka, Aug 05 2011

Examples

			Since a(2) = 17, there are 17 signed permutations of 4 that are equal to their reverse-complements and avoid (-2,-1).  Some of these are: (+1,+3,+2,+4), (+2,-1,-4,+3), (+3,-1,-4,+2), (-1,-2,-3,-4). - _Justin M. Troyka_, Aug 05 2011
		

Crossrefs

Programs

  • Maple
    a := n -> (-2)^n*KummerU(-n, 1, -1/2):
    seq(simplify(a(n)), n=0..17); # Peter Luschny, Feb 12 2020
  • Mathematica
    Table[ n! 2^n LaguerreL[ n, -1/2 ], {n, 0, 12} ]
    f[n_] := Sum[k!*2^k*Binomial[n, k]^2, {k, 0, n}]; Table[ f[n], {n, 0, 17}] (* Robert G. Wilson v, Mar 16 2005 *)
    a = {1, 3}; For[n = 2, n < 13, n++, a = Append[a, (4 n - 1) a[[n]] - 4 (n - 1)^2 a[[n - 1]]]]; a  (* Justin M. Troyka, Aug 05 2011 *)
  • PARI
    {a(n)=n!^2*polcoeff(exp(2*x+x*O(x^n))*sum(m=0,n,x^m/m!^2),n)}

Formula

a(n) = Sum_{k=0..n} k!*2^k*binomial(n, k)^2. - Robert G. Wilson v, Mar 16 2005 [corrected by Ilya Gutkovskiy, Oct 01 2018]
a(n) = Sum_{k=0..n-1} 2^{n-1-k}*[(n-1)! ]^2/[(k!)^2*(n-1-k)! ]. - Huajun Huang (huanghu(AT)auburn.edu), Oct 10 2005
a(0) = 1; a(1) = 3; a(n) = (4n-1) * a(n-1) - 4 (n-1)^2 * a(n-2) for n >= 2. - Justin M. Troyka, Aug 05 2011
E.g.f.: exp(2*x) * Sum_{n>=0} x^n/n!^2 = Sum_{n>=0} a(n)*x^n/n!^2. - Paul D. Hanna, Nov 18 2011
a(n) ~ n^(n+1/4)*2^(n-1/4)*exp(-n+sqrt(2*n)-1/4) * (1 + sqrt(2)/(3*sqrt(n))). - Vaclav Kotesovec, Jun 22 2013
a(n) = (-2)^n*KummerU(-n, 1, -1/2). - Peter Luschny, Feb 12 2020

Extensions

More terms from Vladeta Jovovic, Jan 29 2003

A218272 Infinitesimal generator for transpose of the Pascal matrix A007318 (as upper triangular matrices).

Original entry on oeis.org

0, 1, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0
Offset: 0

Views

Author

Tom Copeland, Oct 24 2012

Keywords

Comments

T is the transpose of A132440.
Let M(t) = exp(t*T) = limit [1 + t*T/n]^n as n tends to infinity.
Then M(1) = the transpose of the lower triangular Pascal matrix A007318, with inverse M(-1).
Given a polynomial sequence p_n(x) with p_0(x)=1 and the lowering and raising operators L and R defined by L P_n(x) = n * P_(n-1)(x) and
R P_n(x) = P_(n+1)(x), the matrix T represents the action of L in the p_n(x) basis. For p_n(x) = x^n, L = D = d/dx and R = x. For p_n(x) = x^n/n!, L = DxD and R = D^(-1).
See A132440 as an analog and more general discussion.
Sum_{n>=0} c_n T^n / n! = e^(c.T) gives the Maurer-Cartan form matrix for the one-dimensional Leibniz group defined by multiplication of a Taylor series by the formal Taylor series e^(c.x) (cf. Olver). - Tom Copeland, Nov 05 2015
From Tom Copeland, Jul 02 2018: (Start)
The transpose Psc^Trn of the lower triangular Pascal matrix Psc = A007318 gives the numerical coefficients of the Maurer-Cartan form matrix M of the Leibniz group Leibniz(n)(1,1) presented on p. 9 of the Olver paper. M = exp[c. * T] with (c.)^n = c_n and T the Lie infinitesimal generator of this entry. The columns e^T are the rows of the Pascal matrix A007318.
M can be obtained by multiplying each n-th column vector of Psc by c_n and then transposing the result; i.e., with the diagonal matrix H = Diag(c_0, c_1, c_2, ...), M = (Psc * H)^Trn = H * Psc^Trn.
M is a matrix representation of the differential operator S = e^{c.*D} with D = d/dx, which acting on x^m gives the Appell polynomial p_m(x) = (c. + x)^m, with (c.)^k = c_k an arbitrary indeterminate except for c_0 = 1. For example, S x^2 = (c. + x)^2 = c_0*x^2 + 2*c_1*x + c_2, and M * (0,0,1,0,0,...)^Trn = (c_2,2*c_1,c_0,0,0,...)^Trn = V, so V^Trn = (0,0,1,0,...) * M^Trn = (0,0,1,0,...) * Psc * H = (c_2,2*c_1,c_0,0,...).
The differential lowering and raising operators for the Appell sequence are given by L = D and R = x + dlog(S)/dD, with L p_n(x = n * p_(n-1)(x) and R p_n(x) = p_(n+1)(x).
(End)

Examples

			Matrix T begins
  0,1;
  0,0,2;
  0,0,0,3;
  0,0,0,0,4;
  0,0,0,0,0,5;
  0,0,0,0,0,0,6;
  ...
		

Crossrefs

Essentially the same as A134402, A132440 and A130460.

Programs

Formula

The matrix operation b = T*a can be characterized in several ways in terms of the coefficients a(n) and b(n), their o.g.f.s A(x) and B(x), or e.g.f.s EA(x) and EB(x):
1) b(n) = (n+1) * a(n+1),
2) B(x) = D A(x), or
3) EB(x) = DxD EA(x),
where D is the derivative w.r.t. x.
So the exponentiated operator can be characterized as
4) exp(t*T) A(x) = exp(t*D) A(x) = A(x+t),
5) exp(t*T) EA(x) = exp(t*DxD) EA(x) = exp[x*a/(1+t*a)]/(1+t*a),
= Sum_{n>=0} (1+t*a)^(-n-1) (x*a)^n/n!, where umbrally
a^n *(1+t*a)^(-n-1) = Sum_{j>0} binomial(n+j,j)a(n+j)t^j,
6) exp(t*T) EA(x) = Sum_{n>=0} a(n) t^n Lag(n,-x/t),
where Lag(n,x) are the Laguerre polynomials (A021009), or
7) [exp(t*T) * a]_n = [M(t) * a]_n
= Sum_{j>=0} binomial(n+j,j)a(n+j)t^j.
For more on the operator DxD, see A021009 and references in A132440.

A222467 Denominator sequence of the n-th convergent of the continued fraction 1/(1 + 2/(2 + 2/(3 + 2/(4 + ...

Original entry on oeis.org

1, 1, 4, 14, 64, 348, 2216, 16208, 134096, 1239280, 12660992, 141749472, 1726315648, 22725602368, 321611064448, 4869617171456, 78557096872192, 1345209881170176, 24370892054807552, 465737368803683840, 9363489160183291904
Offset: 0

Views

Author

Gary Detlefs and Wolfdieter Lang, Mar 21 2013

Keywords

Comments

The corresponding numerator sequence is A222468.
a(n) = Q(n,2) with the denominator polynomials Q of A084950. All the given formulas follow from there. The limit of the continued fraction (0 + K_{k>=1} (2/k))/2 = 1/(1+2/(2+2/(3+2/(4+... is (1/2)*sqrt(2)*BesselI(1,2*sqrt(2))/BesselI(0,2*sqrt(2)) = 0.5631786198117... See A222466 for more digits.
For a combinatorial interpretation in terms of labeled Morse codes see a comment on A084950. Here each dash has label x=2, and the dots have label j if they are at position j. Labels are multiplied and all codes on [1,2,...,n] are summed.

Examples

			a(4) = 4*a(3) + 2*a(2) = 4*14 + 2*4 = 64.
Continued fraction convergent: 1/(1+2/(2+2/(3+2/4))) = 9/16 =  36/64 = A222468(4)/a(4).
Morse code a(4) = 64 from the sum of all 5 labeled codes on [1,2,3,4], one with no dash, three with one dash and one with two dashes:  4! + (3*4 + 1*4 + 1*2)*2 + 2^2 = 64.
		

Crossrefs

Cf. A084950, A221913, A222468, A001040(n+1) (x=1), A058797 (x=-1).

Programs

  • Magma
    I:=[1,4]; [1] cat [n le 2 select I[n] else n*Self(n -1) + 2*Self(n-2): n in [1..30]]; // G. C. Greubel, May 16 2018
  • Mathematica
    RecurrenceTable[{a[0]==a[1]==1,a[n]==n*a[n-1]+2*a[n-2]},a,{n,20}] (* Harvey P. Dale, Jul 06 2017 *)
  • PARI
    m=30; v=concat([1,4], vector(m-2)); for(n=3, m, v[n]=n*v[n-1] + 2*v[n-2]); concat([1], v) \\ G. C. Greubel, May 16 2018
    

Formula

Recurrence: a(n) = n*a(n-1) + 2*a(n-2), a(-1) = 0, a(0 ) =1, n >= 1.
As a sum: a(n) = Sum_{m =0..floor(n/2)} a(n-m,m)*2^m, n >= 0, with a(n,m) = (n!/m!)*binomial(n,m) = |A021009(n,m)| (Laguerre).
Explicit form: a(n) = 2*(w/2)^(n+1)*(BesselI(0,w)*BesselK(n+1,w) - BesselK(0,w)*BesselI(n+1,w)*(-1)^(n+1)) with w := -2*sqrt(2).
E.g.f.: (i*Pi*sqrt(2)/sqrt(1-z))*(BesselJ(1, 2*i*sqrt(2)*sqrt(1-z))*BesselY(0, 2*i*sqrt(2)) - BesselY(1, 2*i*sqrt(2)*sqrt(1-z))*BesselJ(0,2*i*sqrt(2))) with the imaginary unit i = sqrt(-1).
Asymptotics: lim_{n->infinity} a(n)/n! = BesselI(0,2*sqrt(2)) = 4.2523508795026...

A021010 Triangle of coefficients of Laguerre polynomials L_n(x) (powers of x in decreasing order).

Original entry on oeis.org

1, -1, 1, 1, -4, 2, -1, 9, -18, 6, 1, -16, 72, -96, 24, -1, 25, -200, 600, -600, 120, 1, -36, 450, -2400, 5400, -4320, 720, -1, 49, -882, 7350, -29400, 52920, -35280, 5040, 1, -64, 1568, -18816, 117600, -376320, 564480, -322560, 40320, -1, 81, -2592, 42336, -381024, 1905120, -5080320, 6531840, -3265920, 362880
Offset: 0

Views

Author

Keywords

Comments

abs(T(n,k)) = k!*binomial(n,k)^2 = number of k-matchings of the complete bipartite graph K_{n,n}. Example: abs(T(2,2))=2 because in the bipartite graph K_{2,2} with vertex sets {A,B},{A',B'} we have the 2-matchings {AA',BB'} and {AB',BA'}. Row sums of the absolute values yield A002720. - Emeric Deutsch, Dec 25 2004

Examples

			   1;
  -1,   1;
   1,  -4,   2;
  -1,   9, -18,   6;
   1, -16,  72, -96,  24;
  ...
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 799.

Crossrefs

Cf. A002720, A021009, A009940 (row sums).
Central terms: A295383.

Programs

  • Magma
    [[(-1)^(n-k)*Factorial(k)*Binomial(n, k)^2: k in [0..n]]: n in [0..10]]; // G. C. Greubel, Feb 06 2018
  • Maple
    T:=(n,k)->(-1)^(n-k)*k!*binomial(n,k)^2: for n from 0 to 9 do seq(T(n,k),k=0..n) od; # yields sequence in triangular form # Emeric Deutsch, Dec 25 2004
  • Mathematica
    Flatten[ Table[ Reverse[ CoefficientList[n!*LaguerreL[n, x], x]], {n, 0, 9}]] (* Jean-François Alcover, Nov 24 2011 *)
  • PARI
    LaguerreL(n,v='x) = {
      my(x='x+O('x^(n+1)), t='t);
      subst(polcoeff(exp(-x*t/(1-x))/(1-x), n), 't, v);
    };
    concat(apply(n->Vec(n!*LaguerreL(n)), [0..9])) \\ Gheorghe Coserea, Oct 26 2017
    
  • PARI
    row(n) = Vec(n!*pollaguerre(n)); \\ Michel Marcus, Feb 06 2021
    

Formula

T(n, k) = (-1)^(n-k)*k!*binomial(n, k)^2. - Emeric Deutsch, Dec 25 2004

A103213 a(n) = n! * Sum_{k=1..n} binomial(n,k)/k.

Original entry on oeis.org

1, 5, 29, 206, 1774, 18204, 218868, 3036144, 47928816, 850514400, 16783812000, 364865040000, 8666747625600, 223351748524800, 6206847295622400, 185007996436838400, 5887506932836300800, 199216094254423142400
Offset: 1

Views

Author

Ralf Stephan, Jan 28 2005

Keywords

Comments

a(n) is the sum of all terms in the rows of permutations of the powers of 2. For k=1..n, term(k) can be any power of 2 from 0 to k-1; thus for term(3) it may be 1 or 2 or 4. Find all n! rows of permutations and the sum of the terms in all these rows. This sum will be a(n). - J. M. Bergot, Jun 18 2015

Crossrefs

Cf. A021009.

Programs

  • Maple
    S:= series(log((1-2*x)/(1-x))/(x-1), x, 41):
    seq(coeff(S,x,j)*j!,j=1..40); # Robert Israel, Jun 19 2015
  • Mathematica
    a[n_] := n*n!*HypergeometricPFQ[{1, 1, 1-n}, {2, 2}, -1]; Table[a[n], {n, 1, 18}] (* Jean-François Alcover, Nov 28 2013 *)
    Table[n! (-HarmonicNumber[n] - 2^(n+1) Re[LerchPhi[2, 1, n+1]]), {n, 1, 20}] (* Vladimir Reshetnikov, Apr 24 2016 *)

Formula

E.g.f.: log((1-2*x)/(1-x))/(x-1). a(n) = n! * Sum_{k=1..n} (2^k-1)/k. - Vladeta Jovovic, Jan 29 2005
a(n) ~ 2^(n+1)*(n-1)!. - Jean-François Alcover, Nov 28 2013
a(n+4) = 2*(n+3)*(n+2)^2*a(n+1)-(n+3)*(13+5*n)*a(n+2)+(4*n+13)*a(n+3). - Robert Israel, Jun 19 2015
a(n) = -n!*log(2) + Sum_{k>=1} (k+n)!/(2^k*k*k!). - Groux Roland, Dec 18 2010
From Vladimir Reshetnikov, Apr 24 2016: (Start)
a(n) = n!*((n+1)*hypergeom([1, 1, n+2], [2, 2], 1/2)/2 - log(2)).
a(n) = n!*(-H(n) - Re(Beta(2; n+1, 0))).
a(n) = n!*(-H(n) - 2^(n+1)*Re(LerchPhi(2, 1, n+1))), where H(n) is the harmonic number, Beta(z; a, b) is the incomplete Beta function, LerchPhi(z, s, a) is the Lerch transcendent.
(End)
a(n) = -Sum_{k=0..n} (-1)^k*k!*A021009(n, k+1). - Mélika Tebni, Jun 20 2022

A235706 (I + A132440)^3: Coefficients for normalized generalized Laguerre polynomials n!*Lag(n, 3-n, -x).

Original entry on oeis.org

1, 3, 1, 6, 6, 1, 6, 18, 9, 1, 0, 24, 36, 12, 1, 0, 0, 60, 60, 15, 1, 0, 0, 0, 120, 90, 18, 1, 0, 0, 0, 0, 210, 126, 21, 1, 0, 0, 0, 0, 0, 336, 168, 24, 1, 0, 0, 0, 0, 0, 0, 504, 216, 27, 1, 0, 0, 0, 0, 0, 0, 0, 720, 270, 30, 1
Offset: 0

Views

Author

Tom Copeland, Apr 20 2014

Keywords

Comments

The associated Laguerre polynomials n!*Lag(n,3-n,-x) are related to the rook polynomials of a rectangular 3 X n chessboard by R(3,n,x) = n!*x^n*Lag(n,3-n,-1/x), which are also the matching polynomials, or generating function of the number of k-edge matchings, of the complete bipartite graph K(m,n), or biclique (cf. Wikipedia for details).
The formulas here and below can be naturally extended with 3 replaced by any positive integer m. For m = 1 and 2, see unsigned A132013 and A132014. The formulas there can be extrapolated to apply to this matrix.

Examples

			Triangle begins:
  1;
  3,  1;
  6,  6,  1;
  6, 18,  9,  1;
  0, 24, 36, 12,  1;
  0,  0, 60, 60, 15, 1;
  ...
		

Crossrefs

Cf. A007318, A008306 for a generalization, A132013, A132014, A132440, A238363, A238385.
....................................
With 0th row: 1
n-th row: n!*Lag(n,3-n,-x)
....................................
1st: 1!*Lag(1,2,-x) = A062139(1,k,-x)
2nd: 2!*Lag(2,1,-x) = A105278(2,k,x)
3rd: 3!*Lag(3,0,-x) = A021009(3,k,-x)
4th: 4!*Lag(4,-1,-x) = A111596(4,k,-x)
5th: 5!*Lag(5,-2,-x) = cf. x^2*A062139(3,k,x)
6th: 6!*Lag(6,-3,-x) = cf. x^3*A062137(3,k,-x)
....................................
n-th row: x^(n-3)*3!*Lag(3,n-3,-x)
....................................
1st: x^(-2)*3!Lag(3,-2,-x) = cf. x^(-2)*[x^2*A062139(1,k,x)]
2nd: x^(-1)*3!Lag(3,-1,-x) = x^(-1)*A111596(3,k,-x)
3rd: x^0*3!Lag(3,0,-x) = x^0*A021009(3,k,-x)
4th: x^1*3!Lag(3,1,-x) = x^1*A105278(3,k,x)
5th: x^2*3!Lag(3,2,-x) = x^2*A062139(3,k,-x)
6th: x^3*3!Lag(3,3,-x) = x^3*A062137(3,k,-x)

Programs

  • Magma
    /* As triangle */ [[Binomial(3, n-k)*Factorial(n)/Factorial(k): k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Jul 28 2017
  • Mathematica
    Table[Binomial[3, n - k] n! / k!, {n, 0, 9}, {k, 0, n}]//Flatten (* Vincenzo Librandi, Jul 28 2017 *)
  • PARI
    T(n,k) = binomial(3,n-k)*n!/k!
    tabl(nn) = for (n=0, nn, for (k=0, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 28 2017
    
  • PARI
    row(n) = Vecrev(n!*pollaguerre(n, 3-n, -x)); \\ Michel Marcus, Feb 06 2021
    

Formula

T(n,k) = binomial(3,n-k)*n!/k! = binomial(n,k)*3!/(3-n+k)!.
E.g.f.: exp(y*x)(1+y)^3, so this is an Appell sequence of polynomials with lowering operator L= D= d/dx and raising operator R = x + 3/(1+D).
E.g.f. of inverse matrix is exp(x*y)/(1+y)^3.
Multiply the n-th diagonal of the Pascal matrix A007318 by d(0)=1, d(1)=3, d(2)=6, d(3)=6, and d(n)=0 for n>3 to obtain T.
Row polynomials: n!*Lag(n,3-n,-x) = x^(n-3)*3!*Lag(3,n-3,-x) =
(3!/(3-n)!)*K(-n,3-n+1,-x) where K is Kummer's confluent hypergeometric function (as a limit of n+c as c tends to zero).
T = (I + A132440)^3 = exp[3*(A238385-I)]. I = identity matrix.
Operationally, n!Lag(n,3-n,-:xD:) = x^(n-3)*:Dx:^n*x^(3-n) = x^(-3)*:xD:^n*x^3 = n!*binomial(xD+3,n) = n!*binomial(3,n)*K(-n,3-n+1,-:xD:) where :AB:^n = A^n*B^n for any two operators.
n-th row polynomial: n!*Sum_{k = 0..n} (-1)^(n-k)*binomial(n,k)*Lag(k,3,-x). - Peter Bala, Jul 25 2021

A001810 a(n) = n!*n*(n-1)*(n-2)/36.

Original entry on oeis.org

0, 0, 0, 1, 16, 200, 2400, 29400, 376320, 5080320, 72576000, 1097712000, 17563392000, 296821324800, 5288816332800, 99165306240000, 1952793722880000, 40311241850880000, 870722823979008000, 19645683716026368000, 462251381553561600000, 11325158848062259200000
Offset: 0

Views

Author

Keywords

Comments

a(n) is the total number of 3-2-1 patterns in all permutations on [n]. This is because there are n! permutations, binomial(n,3) triples in each one and the probability that a given triple of entries in a random permutation form a 3-2-1 pattern (or any other specified pattern of length 3) is 1/6. - David Callan, Oct 26 2006
Old name was "Coefficients of Laguerre polynomials".

Examples

			G.f. = x^3 + 16*x^4 + 200*x^5 + 2400*x^6 + 29400*x^7 + 376320*x^8 + ...
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 799.
  • Cornelius Lanczos, Applied Analysis. Prentice-Hall, Englewood Cliffs, NJ, 1956, p. 519.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Magma
    [Factorial(n)*n*(n-1)*(n-2)/36: n in [0..20]]; // G. C. Greubel, May 16 2018
  • Maple
    [seq(n!*n*(n-1)*(n-2)/36,n=0..30)];
    with(combstruct):ZL:=[st, {st=Prod(left, right), left=Set(U, card=r+1), right=Set(U, card=1)}, labeled]: subs(r=2, stack): seq(count(subs(r=2, ZL), size=m), m=0..20) ; # Zerinvary Lajos, Feb 07 2008
  • Mathematica
    Table[n! n*(n-1)*(n-2)/36, {n, 0, 20}] (* T. D. Noe, Aug 10 2012 *)
  • PARI
    for(n=0,20, print1(n!*n*(n-1)*(n-2)/36, ", ")) \\ G. C. Greubel, May 16 2018
    
  • Sage
    [factorial(m) * binomial(m, 3) / 6 for m in range(22)]  # Zerinvary Lajos, Jul 05 2008
    

Formula

a(n) = -A021009(n, 3), n >= 0. a(n) = ((n!/3!)^2)/(n-3)!, n >= 3.
E.g.f.: x^3/(3!*(1-x)^4).
If we define f(n,i,x) = Sum_{k=i..n} Sum_{j=i..k} binomial(k,j) * Stirling1(n,k) * Stirling2(j,i) * x^(k-j) then a(n) = (-1)^(n-1) * f(n,3,-4), (n >= 3). - Milan Janjic, Mar 01 2009
a(n) = Sum_{k>0} k * A263771(n,k). - Alois P. Heinz, Oct 27 2015
From Amiram Eldar, May 02 2022: (Start)
Sum_{n>=3} 1/a(n) = 9*(2*e + gamma - Ei(1) - 4), where e = A001113, gamma = A001620, and Ei(1) = A091725.
Sum_{n>=3} (-1)^(n+1)/a(n) = 63*(gamma - Ei(-1)) - 36*(1/e + 1), where Ei(-1) = -A099285. (End)

Extensions

Edited by N. J. A. Sloane, Apr 12 2014
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