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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A180047 Coefficient triangle of the numerators of the (n-th convergents to) the continued fraction w/(1 + w/(2 + w/(3 + w/(...)))).

Original entry on oeis.org

0, 0, 1, 0, 2, 0, 6, 1, 0, 24, 6, 0, 120, 36, 1, 0, 720, 240, 12, 0, 5040, 1800, 120, 1, 0, 40320, 15120, 1200, 20, 0, 362880, 141120, 12600, 300, 1, 0, 3628800, 1451520, 141120, 4200, 30, 0, 39916800, 16329600, 1693440, 58800, 630, 1, 0, 479001600
Offset: 0

Views

Author

Wouter Meeussen, Aug 08 2010

Keywords

Comments

Equivalence to the binomial formula needs formal proof. This c.f. converges to A052119 = 0.697774657964.. = BesselI(1,2)/BesselI(0,2) for w = 1.

Examples

			Triangle starts:
  0;
  0,   1;
  0,   2;
  0,   6,   1;
  0,  24,   6;
  0, 120,  36,  1;
  0, 720, 240, 12;
The numerator of w/(1+w/(2+w/(3+w/(4+w/5)))) equals 120*w + 36*w^2 + w^3.
		

Crossrefs

Programs

  • Mathematica
    Table[CoefficientList[Numerator[Together[Fold[w/(#2+#1) &,Infinity,Reverse @ Table[k,{k,1,n}]]]],w],{n,16}]; (* or equivalently *) Table[(n-m+1)!/m! *Binomial[n-m,m-1], {n,0,16}, {m,0,Floor[n/2+1/2]}]

Formula

T(n,m) = (n-m+1)!/m!*binomial(n-m, m-1) for n >= 0, 0 <= m <= (n+1)/2.

A293125 Expansion of e.g.f.: exp(-x/(1+x)).

Original entry on oeis.org

1, -1, 3, -13, 73, -501, 4051, -37633, 394353, -4596553, 58941091, -824073141, 12470162233, -202976401213, 3535017524403, -65573803186921, 1290434218669921, -26846616451246353, 588633468315403843, -13564373693588558173, 327697927886085654441
Offset: 0

Views

Author

Seiichi Manyama, Sep 30 2017

Keywords

Comments

For n >= 1, gives row sums of A008297, triangle of Lah numbers. - Daniel Forgues, Oct 12 2019

Crossrefs

Column k=0 of A293134.

Programs

  • GAP
    a:=[-1,3];; for n in [3..25] do a[n]:=-(2*n-1)*a[n-1]-(n-2)*(n-1)*a[n-2]; od; Concatenation([1], a); # G. C. Greubel, Dec 04 2018
  • Magma
    [1] cat [(-1)^n*Factorial(n)*(&+[Binomial(n-1, j)/Factorial(j+1): j in [0..n-1]]): n in [1..30]]; // G. C. Greubel, Dec 04 2018
    
  • Mathematica
    CoefficientList[Series[E^(-x/(1+x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Sep 30 2017 *)
    a[n_] := If[n == 0, 1, (-1)^n n! Hypergeometric1F1[1 - n, 2, -1]];
    Table[a[n], {n, 0, 20}] (* Peter Luschny, Oct 13 2019 *)
  • PARI
    my(x='x+O('x^21)); Vec(serlaplace(exp(-x/(1+x))))
    
  • Sage
    [1] + [(-1)^n*factorial(n)*sum(binomial(n-1,j)/factorial(j+1) for j in (0..n-1)) for n in (1..30)] # G. C. Greubel, Dec 04 2018
    

Formula

a(n) = (-1)^n * A000262(n).
From Vaclav Kotesovec, Sep 30 2017: (Start)
a(n) = -(2*n-1)*a(n-1) - (n-2)*(n-1)*a(n-2).
a(n) ~ (-1)^n * n^(n-1/4) * exp(-1/2 + 2*sqrt(n) - n) / sqrt(2) * (1 - 5/(48*sqrt(n)) - 95/(4608*n)). (End)
a(n) = (-1)^n * n! * Sum_{j=0..n-1} binomial(n-1, j)/(j+1)!, for n > 0. - G. C. Greubel, Dec 04 2018
a(n) = (-1)^n*n!*hypergeom([1 - n], [2], -1) for n > 0. - Peter Luschny, Oct 13 2019

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

Views

Author

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

A086915 Triangle read by rows: T(n,k) = 2^k * (n!/k!)*binomial(n-1,k-1).

Original entry on oeis.org

2, 4, 4, 12, 24, 8, 48, 144, 96, 16, 240, 960, 960, 320, 32, 1440, 7200, 9600, 4800, 960, 64, 10080, 60480, 100800, 67200, 20160, 2688, 128, 80640, 564480, 1128960, 940800, 376320, 75264, 7168, 256, 725760, 5806080, 13547520, 13547520, 6773760, 1806336
Offset: 1

Author

Vladeta Jovovic, Sep 24 2003

Keywords

Comments

Also the Bell transform of A052849(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016
The coefficients of n! * L_n(-2*x,-1), where n! * L_n(-x,-1) are the normalized, unsigned Laguerre polynomials of order -1 of A105278, also known as the Lah polynomials, which are also a shifted version of n! * L_n(-x,1). Cf. p. 8 of the Gross and Matytsin link. - Tom Copeland, Sep 30 2016

Examples

			Triangle begins:
   2;
   4,   4;
  12,  24,  8;
  48, 144, 96, 16;
  ...
		

Crossrefs

Cf. A008297, A052897 (row sums), A059110, A079621, A105278.

Programs

  • Magma
    [Factorial(n)*Binomial(n-1,k-1)*2^k/Factorial(k): k in [1..n], n in [1..10]]; // G. C. Greubel, May 23 2018
  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ...) as column 0.
    BellMatrix(n -> 2*(n+1)!, 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    Flatten[Table[n!/k! Binomial[n-1,k-1]2^k,{n,10},{k,n}]] (* Harvey P. Dale, May 25 2011 *)
    BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    B = BellMatrix[2*(#+1)!&, rows = 12];
    Table[B[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 28 2018, after Peter Luschny *)
  • PARI
    for(n=1,10, for(k=1, n, print1(n!/k!*binomial(n-1,k-1)*2^k, ", "))) \\ G. C. Greubel, May 23 2018
    

Formula

E.g.f.: exp(2*x*y/(1-x)).
From G. C. Greubel, Feb 23 2021: (Start)
T(n, k) = (-2)^k * A008297(n, k) = 2^k * A105278(n, k).
Sum_{k=1..n} T(n, k) = 2 * n! * Hypergeometric1F1([1-n], [2], -2) = 2*(n-1)! * LaguerreL(n-1, 1, -2) = A253286(n, 2). (End)

A111598 Lah numbers: a(n) = n!*binomial(n-1,7)/8!.

Original entry on oeis.org

1, 72, 3240, 118800, 3920400, 122316480, 3710266560, 111307996800, 3339239904000, 100919250432000, 3088129063219200, 96012739965542400, 3040403432242176000, 98228418580131840000, 3241537813144350720000
Offset: 8

Author

Wolfdieter Lang, Aug 23 2005

Keywords

References

  • Louis Comtet, Advanced Combinatorics, Reidel, 1974, p. 156.
  • John Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 44.

Crossrefs

Column 8 of unsigned A008297 and A111596.
Column 7 of A111597.

Programs

  • Magma
    [Factorial(n-8)*Binomial(n,8)*Binomial(n-1,7): n in [8..35]]; // G. C. Greubel, May 10 2021
    
  • Mathematica
    Table[(n-8)!*Binomial[n-1,7]*Binomial[n,8], {n,8,35}] (* G. C. Greubel, May 10 2021 *)
  • Sage
    [factorial(n-8)*binomial(n,8)*binomial(n-1,7) for n in (8..35)] # G. C. Greubel, May 10 2021

Formula

E.g.f.: ((x/(1-x))^8)/8!.
a(n) = (n!/8!)*binomial(n-1, 8-1).
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*f(n,8,-8), (n>=8). - Milan Janjic, Mar 01 2009
From Amiram Eldar, May 02 2022: (Start)
Sum_{n>=8} 1/a(n) = 61096*(gamma - Ei(1)) + 54544*e - 338732/5, where gamma = A001620, Ei(1) = A091725 and e = A001113.
Sum_{n>=8} (-1)^n/a(n) = 2107448*(gamma - Ei(-1)) - 1257760/e - 6080436/5, where Ei(-1) = -A099285. (End)

A247500 Triangle read by rows: T(n, k) = n!*binomial(n + 1, k)/(k + 1)!, 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 2, 3, 1, 6, 12, 6, 1, 24, 60, 40, 10, 1, 120, 360, 300, 100, 15, 1, 720, 2520, 2520, 1050, 210, 21, 1, 5040, 20160, 23520, 11760, 2940, 392, 28, 1, 40320, 181440, 241920, 141120, 42336, 7056, 672, 36, 1, 362880, 1814400, 2721600, 1814400, 635040, 127008, 15120, 1080, 45, 1
Offset: 0

Author

Peter Luschny, Oct 17 2014

Keywords

Comments

An alternative definition would have been: (n-k)!*N(n,k) where N(n,k) are the little Narayana numbers A090181(n,k). This adds a first column (1,0,0,...) to the triangle and amounts to (Gamma(n)*Gamma(n+1))/(Gamma(k)*Gamma(k+1)*Gamma(n-k+2)). - Peter Luschny, Jun 18 2015
From Peter Bala, Sep 03 2023: (Start)
Let E(y) = Sum_{n >= 0} y^n/(n+1)!. Then this triangle is the generalized Riordan array (E(y), y) with respect to the sequence n!*(n+1)! as defined in Wang and Wang.
Let B(y) = Sum_{n >= 0} y^n/(n!*(n+1)!) = 1/sqrt(y)*BesselI(1,2*sqrt(y)). A generating function for the triangle is E(y)*B(x*y) = 1 + (1 + x)*y/(1!*2!) + (2 + 3*x + x^2)*y^2/(2!*3!) + (6 + 12*x + 6*x^2 + x^3)*y^3/(3!*4!) + .... Cf. A105278 with a generating function exp(y)*B(x*y).
The n-th power of this array has a generating function E(y)^n*B(x*y). In particular, the matrix inverse has a generating function B(x*y)/E(y). (End)

Examples

			Triangle begins:
                      1;
                   1,    1;
                2,    3,    1;
             6,   12,    6,    1;
         24,   60,   40,   10,    1;
     120,  360,  300,  100,   15,    1;
  720, 2520, 2520, 1050,  210,   21,    1;
		

Crossrefs

Cf. A247499 (row sums), A008297.
Cf. A204515 (central terms), A105278, A004736.

Programs

  • Haskell
    a247500 n k = a247500_tabl !! n !! k
    a247500_row n = a247500_tabl !! n
    a247500_tabl = zipWith (zipWith div) a105278_tabl a004736_tabl
    -- Reinhard Zumkeller, Oct 19 2014
  • Magma
    /* triangle */ [[Factorial(n)/Factorial(k) * Binomial(n+2, k+1) /(n+2): k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Oct 18 2014
    
  • Maple
    T := (n,k) -> ((k+1)*(n+1)*GAMMA(n+1)^2)/(GAMMA(k+2)^2*GAMMA(n-k+2));
    A247500 := (n, k) -> (n!/(k+1)!)*binomial(n + 1, k):
  • Mathematica
    Table[((k + 1) (n + 1) Gamma[n + 1]^2)/(Gamma[k + 2]^2*
    Gamma[n - k + 2]), {n, 0, 9}, {k, 0, n}] // Flatten (* Michael De Vlieger, Jun 19 2015 *)

Formula

T(n, k) = ((k+1)*(n+1)*Gamma(n+1)^2)/(Gamma(k+2)^2 *Gamma(n-k+2)). (original name)
T(n, k) = (n!/k!)*C(n+2, k+1)/(n+2).
T(n, 0) = A000142(n).
T(n, n-1) = A000217(n).
T(n+1, 1) = A001710(n+2).
Sum_{k=0..n} T(n, k) = A247499(n).
L(n+1, k+1) = T(n-1, k)*P(n) for n>=1 and 0<=k<=n; here L(n,k) denote the unsigned Lah numbers and P(n) the pronic numbers. - Peter Luschny, Oct 18 2014
T(n,k) = A105278(n+1,k+1) / (n+1-k), k=0..n. - Reinhard Zumkeller, Oct 19 2014
From Peter Bala, May 24 2023: (Start)
Triangle equals A164652 * A008277 (assuming the same offset for the three triangles).
This is equivalent to the Stirling number identity Sum_{i = 0..n} (n+1)!/(i+1)!* binomial(n,i)*Stirling1(i+1,k) = (-1)^(n+k+1)*Stirling1(n+1,k) for n, k >= 0. (End)

Extensions

Name updated by Peter Luschny, Jan 09 2022

A055924 Exponential transform of Stirling1 triangle A008275.

Original entry on oeis.org

1, -1, 2, 2, -6, 5, -6, 22, -30, 15, 24, -100, 175, -150, 52, -120, 548, -1125, 1275, -780, 203, 720, -3528, 8120, -11025, 9100, -4263, 877, -5040, 26136, -65660, 101535, -101920, 65366, -24556, 4140, 40320, -219168, 590620, -1009260, 1167348, -920808, 478842, -149040, 21147
Offset: 1

Author

Keywords

Comments

|a(n,k)| = number of sets of permutations of {1,...,n} with k total cycles.
From David Callan, Sep 20 2007: (Start)
|a(n,k)| = Stirling1(n, k) * Bell(k) counts the above sets of permutations. To see this, recall that Stirling1(n, k) is the number of permutations of [n]={1,...,n} with k cycles and Bell(k) is the number of set partitions of [k].
Given such a permutation and set partition, write the permutation in standard cycle form (smallest entry first in each cycle and first entries decreasing left to right). For example, with n=15 and k=6, {{10}, {6, 11}, {5, 7, 15}, {3, 13, 12, 8}, {2, 14, 9}, {1, 4}} is in this standard cycle form.
Then combine cycles as specified by the partition to form a set of lists. For example, the partition 156-24-3 would yield {{10, 2, 14, 9, 1, 4}, {6, 11, 3, 13, 12, 8}, {5, 7, 15}}. The original first entries are now the record left-to-right lows.
Finally, apply to each list the well known transformation that sends # record lows to # cycles. The example yields {{4, 14, 1, 2, 10, 9}, {13, 11, 3, 6, 8, 12}, {7, 15, 5}}. This is a bijection to sets of lists (i.e. permutations) with a total of k cycles, as required. (End)

Examples

			Triangle begins:
   1;
  -1,    2;
   2,   -6,   5;
  -6,   22, -30,   15;
  24, -100, 175, -150, 52;
  ...
|a(3,2)| = 6 because (12)(3), (12)|(3), (13)(2), (13)|(2), (23)(1), (23)|(1).
		

Crossrefs

Row sums of |a(n,k)| give A000262.

Formula

E.g.f.: exp((1+x)^y-1).
a(n,k) = Stirling1(n,k) * Bell(k). - Vladeta Jovovic, Feb 01 2003

A145118 Denominator polynomials for continued fraction generating function for n!.

Original entry on oeis.org

1, 1, 1, -1, 1, -2, 1, -4, 2, 1, -6, 6, 1, -9, 18, -6, 1, -12, 36, -24, 1, -16, 72, -96, 24, 1, -20, 120, -240, 120, 1, -25, 200, -600, 600, -120, 1, -30, 300, -1200, 1800, -720, 1, -36, 450, -2400, 5400, -4320, 720, 1, -42, 630, -4200, 12600, -15120
Offset: 0

Author

Paul Barry, Oct 02 2008

Keywords

Comments

Row sums are A056920. T(n,1) gives quarter squares A002620. T(n,2) appears to coincide with 2*A000241(n+1).

Examples

			Triangle begins:
1;
1;
1,  -1;
1,  -2;
1,  -4,   2;
1,  -6,   6;
1,  -9,  18,    -6;
1, -12,  36,   -24;
1, -16,  72,   -96,   24;
1, -20, 120,  -240,  120;
1, -25, 200,  -600,  600,  -120;
1, -30, 300, -1200, 1800,  -720;
1, -36, 450, -2400, 5400, -4320, 720;
		

Crossrefs

Programs

  • Maple
    T:= (n, k)-> (-1)^k* binomial(iquo(n+1, 2),k) *binomial(iquo(n, 2), k)*k!:
    seq (seq (T(n, k), k=0..iquo(n, 2)), n=0..16);  # Alois P. Heinz, Dec 04 2012

Formula

T(n,k) = (-1)^k C(floor((n+1)/2),k) * C(floor(n/2),k)*k!.

A176021 Triangle T(n, k) = 1 - (-1)^n*(n! + 1) + A176013(n, k) + A176013(n, n-k+1) read by rows.

Original entry on oeis.org

1, 1, 1, 1, -10, 1, 1, 72, 72, 1, 1, -528, -678, -528, 1, 1, 4770, 6780, 6780, 4770, 1, 1, -48025, -87568, -68458, -87568, -48025, 1, 1, 524384, 1287776, 947520, 947520, 1287776, 524384, 1, 1, -6169282, -19982590, -18010942, -10305790, -18010942, -19982590, -6169282, 1
Offset: 1

Author

Roger L. Bagula, Apr 06 2010

Keywords

Comments

Row sums are: 1, 2, -8, 146, -1732, 23102, -339642, 5519362, -98631416, 1926628022, ...

Examples

			Triangle begins as:
  1;
  1,        1;
  1,      -10,         1;
  1,       72,        72,         1;
  1,     -528,      -678,      -528,         1;
  1,     4770,      6780,      6780,      4770,         1;
  1,   -48025,    -87568,    -68458,    -87568,    -48025,         1;
  1,   524384,   1287776,    947520,    947520,   1287776,    524384,        1;
  1, -6169282, -19982590, -18010942, -10305790, -18010942, -19982590, -6169282, 1;
		

Crossrefs

Programs

  • Magma
    A176013:= func< n,k | (-1)^n*(Factorial(n)/(k*Factorial(k)))*Binomial(n-1, k-1)*Binomial(n, k-1) >;
    [1 - (-1)^n*(Factorial(n) + 1) + A176013(n, k) + A176013(n, n-k+1) : k in [1..n], n in [1..12]]; // G. C. Greubel, Feb 08 2021
  • Mathematica
    A176013[n_, k_]:= (-1)^n*(n!/(k*k!))*Binomial[n-1, k-1]*Binomial[n, k-1];
    T[n_, m_]:= 1 - (-1)^n*(n! + 1) + A176013[n, k] + A176013[n, n-k+1];
    Table[T[n, k], {n, 12}, {k, n}]//Flatten
  • Sage
    def A176013(n, k): return (-1)^n*(factorial(n)/(k*factorial(k)))*binomial(n-1, k-1)*binomial(n, k-1)
    flatten([[1 - (-1)^n*(factorial(n) + 1) + A176013(n, k) + A176013(n, n-k+1) for k in (1..n)] for n in (1..12)]) # G. C. Greubel, Feb 08 2021
    

Formula

T(n, k) = 1 - (-1)^n*(n! + 1) + A176013(n, k) + A176013(n, n-k+1).
T(n, k) = 1 - (-1)^n*(n! + 1) + binomial(n+1, k)*( A008297(n, k) + A008297(n, n-k+1) )/(n+1). - G. C. Greubel, Feb 08 2021

Extensions

Edited by G. C. Greubel, Feb 08 2021
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