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 1-10 of 72 results. Next

A102221 Column 0 of triangular matrix A102220, which equals [2*I - A008459]^(-1).

Original entry on oeis.org

1, 1, 5, 55, 1077, 32951, 1451723, 87054773, 6818444405, 675900963271, 82717196780955, 12248810651651333, 2158585005685222491, 446445657799551807541, 107087164031952038620481, 29487141797206760561836055, 9238158011747884080353808245
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2004

Keywords

Comments

a(n) is the number of ways to form an ordered pair of n-permutations and then choose a subset of its common descent set. Cf. A192721. - Geoffrey Critzer, Apr 29 2023

Crossrefs

Row sums of A192722.
Column k=2 of A326322.

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1,
          add(b(n-i)*binomial(n, i)/i!, i=1..n))
        end:
    a:= n-> b(n)*n!:
    seq(a(n), n=0..20);  # Alois P. Heinz, May 11 2016
  • Mathematica
    Rest[CoefficientList[Series[1/(2-BesselJ[0, 2*I*Sqrt[x]]), {x, 0, 20}], x] * Range[0, 20]!^2] (* Vaclav Kotesovec, Mar 02 2014 *)
    m = 20; CoefficientList[1/(2 - BesselI[0, 2 Sqrt[x]]) + O[x]^m, x] Range[0, m - 1]!^2 (* Jean-François Alcover, Jun 11 2019, after Vladeta Jovovic *)
    b[n_] := b[n] = If[n==0, 1, Sum[b[n-i] Binomial[n, i]/i!, {i, 1, n}]];
    a[n_] := b[n] n!;
    a /@ Range[0, 20] (* Jean-François Alcover, Dec 03 2020, after Alois P. Heinz *)
  • PARI
    a(n)=if(n==0,1,sum(k=0,n-1,binomial(n,k)^2*a(k)))
    
  • Sage
    L = taylor(1/(1-x*hypergeometric((1,),(2,2),x)),x,0,14).list()
    [factorial(i)^2*c for (i,c) in enumerate(L)] # Peter Luschny, Jul 28 2015

Formula

a(n) = Sum_{k=0..n-1} C(n, k)^2*a(k) for n>0, with a(0)=1.
a(n) = A102220(n+k, k)/C(n+k, k)^2 for k>=0.
Sum_{n>=0} a(n)*x^n/n!^2 = 1/(2-BesselI(0,2*sqrt(x))). - Vladeta Jovovic, Jul 17 2006
a(n) ~ c * (n!)^2 / r^n, where r = 0.81712266563155429332453954757369795... is the root of the equation BesselJ(0, 2*I*sqrt(x))=2, and c = 0.833570458821600548332410448635741072476086046022299770387... = 1/(sqrt(r) * BesselI(1, 2*sqrt(r))). - Vaclav Kotesovec, Mar 02 2014, updated Apr 01 2018
From Geoffrey Critzer, Apr 29 2023: (Start)
Sum_{n>=0} a(n)*z^n/(n!)^2 = 1/(2-E(z)) where E(z) = Sum_{n>=0} z^n/(n!)^2.
a(n) = Sum_{k=0..n-1} A192721(n,k)*2^k. (End)

Extensions

Content moved from A192723 to this sequence by Alois P. Heinz, Sep 11 2019

A102223 Column 0 of triangular matrix A102222, which equals -log[2*I - A008459].

Original entry on oeis.org

0, 1, 3, 22, 323, 7906, 290262, 14919430, 1022475715, 90094491994, 9923239949978, 1335853771297750, 215797095378591542, 41198645313603207990, 9176288655853717238830, 2358300288047799986966722
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2004

Keywords

Comments

Triangle A008459 consists of squared binomial coefficients.

Examples

			a(2) = 3 = 1 + (1*0*0 + 4*1*1)/2,
a(3) = 22 = 1 + (1*0*0 + 9*1*1 + 9*2*3)/3,
a(4) = 323 = 1 + (1*0*0 + 16*1*1 + 36*2*3 + 16*3*22)/4,
a(5) = 7906 = 1 + (1*0*0 + 25*1*1 + 100*2*3 + 100*3*22 + 25*4*323)/5.
		

Crossrefs

Programs

  • PARI
    a(n)=if(n<1,0,1+sum(k=0,n-1,binomial(n,k)^2*k*a(k))/n)

Formula

a(n) = 1 + (1/n)*Sum_{k=0..n-1} C(n, k)^2*k*a(k) for n>0, with a(0)=0.
Sum_{n>=0} a(n)*x^n/n!^2 = -log(2-BesselI(0,2*sqrt(x))). - Vladeta Jovovic, Jul 16 2006

A288876 a(n) = binomial(n+4, n)^2. Square of the fifth diagonal sequence of A007318 (Pascal). Fifth diagonal sequence of A008459.

Original entry on oeis.org

1, 25, 225, 1225, 4900, 15876, 44100, 108900, 245025, 511225, 1002001, 1863225, 3312400, 5664400, 9363600, 15023376, 23474025, 35820225, 53509225, 78411025, 112911876, 160022500, 223502500, 308002500, 419225625, 564110001, 751034025, 990046225, 1293121600, 1674446400, 2150733376
Offset: 0

Views

Author

Wolfdieter Lang, Jul 27 2017

Keywords

Comments

This is also the square of the fifth (k = 4) column sequence (without leading zeros) of the Pascal triangle A007318. For the triangle with the squares of the entries of Pascal's triangle see A008459.
For the square of the (d+1)-th diagonal sequence of A007318, PD2(d,n) = binomial(d + n, n)^2, d >= 0, one finds the o.g.f. GPD2(d, x) = Sum_{n>=0} PD2(d,n)*x^n in the following way. Compute the compositional inverse (Lagrange inversion formula) of y(t,x) = x*(1 - t/(1-x)) w.r.t. x, that is x = x(t,y). Then -log(1 - x(t,y)) = Sum_{d=0} y^(d+1)/(d+1)*GPD2(d, x). The r.h.s. can be called the logarithmic generating function (l.g.f.) of the o.g.f.s of the square of the diagonals of Pascal's triangle.
This computation was inspired by an article by P. Bala (see a link in A112007) on the diagonal sequences of special Sheffer triangles (1, f(t)) (Sheffer triangles are there called exponential Riordan triangles, and f is called F). This can be generalized to Sheffer (g, f). For general Riordan triangles R = (G(x), F(x)) a similar analysis can be done. The present entry is then obtained for example of the Pascal triangle P = (1/(1-x), x/(1-x)).
The o.g.f.s for the square of the diagonals of Pascal's triangle turn out to be GPD2(d, x) = P(d,x)/(1 - x)^(2*d+1), with the numerator polynomials given by row n of triangle A008459 (squares of the entries of Pascal's triangle): P(d, x) = Sum_{k=0..d} A008459(d, k)*x^k.

Crossrefs

The squares of the first diagonals are in A000012, A000290(n+1), A000537, A001249 (for d = 0..3).

Programs

Formula

a(n) = binomial(n+4, n)^2, n >= 0.
O.g.f.: (1 + 16*x + 36*x^2 + 16*x^3 + x^4)/(1 - x)^9. (See a comment above and row n=4 of A008459.)
E.g.f: exp(x)*(1 + 24*x + 176*x^2/2! + 624*x^3/3! + 1251*x^4/4!+ 1500*x^5/5!+ 1070*x^6/6! + 420*x^7/7! + 70*x^8/8!), computed from the o.g.f with the formulas (23) - (25) of the W. Lang link given in A060187.
From Amiram Eldar, Sep 20 2022: (Start)
Sum_{n>=0} 1/a(n) = 160*Pi^2/3 - 1576/3.
Sum_{n>=0} (-1)^n/a(n) = 512*log(2)/3 - 352/3. (End)

A055133 Matrix inverse of A008459 (squares of entries of Pascal's triangle).

Original entry on oeis.org

1, -1, 1, 3, -4, 1, -19, 27, -9, 1, 211, -304, 108, -16, 1, -3651, 5275, -1900, 300, -25, 1, 90921, -131436, 47475, -7600, 675, -36, 1, -3081513, 4455129, -1610091, 258475, -23275, 1323, -49, 1, 136407699, -197216832, 71282064, -11449536, 1033900, -59584, 2352, -64, 1
Offset: 0

Views

Author

Christian G. Bower, Apr 25 2000

Keywords

Comments

Let E(y) = Sum_{n >= 0} y^n/n!^2 = BesselJ(0,2*sqrt(-y)). Then this triangle is the generalized Riordan array (1/E(y), y) with respect to the sequence n!^2 as defined in Wang and Wang. - Peter Bala, Jul 24 2013

Examples

			Table T(n,k) (with rows n >= 0 and columns k >= 0) begins as follows:
      1;
     -1,       1;
      3,      -4,     1;
    -19,      27,    -9,     1;
    211,    -304,   108,   -16,   1;
  -3651,    5275, -1900,   300, -25,   1;
  90921, -131436, 47475, -7600, 675, -36, 1;
  ... [edited by _Petros Hadjicostas_, Aug 24 2019]
From _Peter Bala_, Jul 24 2013: (Start)
Function   |        Real zeros to 5 decimal places
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
R(5,x)     | 1, 5.40649,  7.23983
R(10,x)    | 1, 5.26894, 12.97405, 18.53109
R(15,x)    | 1, 5.26894, 12.94909, 24.04769, 33.87883
R(20,x)    | 1, 5.26894, 12.94909, 24.04216, 38.54959, 53.32419
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
E(alpha*x) | 1, 5.26894, 12.94909, 24.04216, 38.54835, 56.46772, ...
where alpha = -1.44579 64907 ... ( = -(A115365/2)^2).
Note: The n-th zero of E(alpha*x) may be calculated in Maple 17 using the instruction evalf( (BesselJZeros(0,n)/BesselJZeros(0,1))^2 ). (End)
		

Crossrefs

Cf. A000275, A008459 (matrix inverse), A115365.

Programs

  • Maple
    T:= proc(n) local M;
           M:= Matrix(n+1, (i, j)-> binomial(i-1, j-1)^2)^(-1);
           seq(M[n+1, i], i=1..n+1)
        end:
    seq(T(n), n=0..10);  # Alois P. Heinz, Mar 14 2013
  • Mathematica
    T[n_] := Module[{M}, M = Table[Binomial[i-1, j-1]^2, {i, 1, n+1}, {j, 1, n+1}] // Inverse; Table[M[[n+1, i]], {i, 1, n+1}]]; Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Nov 28 2015, after Alois P. Heinz *)

Formula

T(n, k) = (-1)^(n+k)*A000275(n-k)*C(n, k)^2.
From Peter Bala, Jul 24 2013: (Start)
Let E(y) = Sum_{n >= 0} y^n/n!^2 = BesselJ(0,2*sqrt(-y)). Generating function: E(x*y)/E(y) = 1 + (-1 + x)*y + (3 - 4*x + x^2)*y^2/2!^2 + (-19 + 27*x - 9*x^2 + x^3)*y^3/3!^2 + ....
The n-th power of this array has a generating function E(x*y)/E(y)^n. In particular, the matrix inverse A008459 has a generating function E(y)*E(x*y).
Recurrence equation for the row polynomials: R(n,x) = x^n - Sum_{k = 0..n-1} binomial(n,k)^2*R(k,x) with initial value R(0,x) = 1.
There appears to be a connection between the zeros of the Bessel function E(x) and the real zeros of the row polynomials R(n,x). Let alpha denote the root of E(x) = 0 that is smallest in absolute magnitude. Numerically, alpha = -1.44579 64907 ... ( = -(A115365/2)^2). It appears that the real zeros of R(n,x) approach zeros of E(alpha*x) as n increases. A numerical example is given below. Indeed, it may be the case that lim_{n -> inf} R(n,x)/R(n,0) = E(alpha*x) for arbitrary complex x. (End)

A101981 Column 0 of triangle A101980, which is the matrix logarithm of A008459 (squared entries of Pascal's triangle).

Original entry on oeis.org

0, 1, -1, 4, -33, 456, -9460, 274800, -10643745, 530052880, -32995478376, 2510382661920, -229195817258100, 24730000147369440, -3113066087894608560, 452168671458789789504, -75059305956331837485345, 14121026957032156557396000, -2988687741694684876495689040
Offset: 0

Views

Author

Paul D. Hanna, Dec 23 2004

Keywords

Comments

This sequence is a signed version of A002190 and is related to Bessel functions.

Crossrefs

Programs

  • Maple
    a:= n-> (-1)^(n+1)*coeff (series (-ln(BesselJ(0, 2*sqrt(x))), x, n+1), x, n)*(n!)^2: seq (a(n), n=0..30); # Alois P. Heinz, Oct 27 2012
  • Mathematica
    a[n_] := (-1)^(n+1) n!^2 SeriesCoefficient[-Log[BesselJ[0, 2 Sqrt[x]]], {x, 0, n}];
    Table[a[n], {n, 0, 18}] (* Jean-François Alcover, Jul 26 2018 *)
  • PARI
    {a(n)=sum(m=1,n,(-1)^(m-1)* (matrix(n+1,n+1,i,j,if(i>j,binomial(i-1,j-1)^2))^m/m)[n+1,1])}

Formula

a(n) = (-1)^(n+1)*A002190(n) for n>=0.
a(n) = 1 - Sum_{j=1..k-1} binomial(k, j)*binomial(k-1, j-1)*a(j) for n >= 1. See Günther & Schmidt link p.5. - Michel Marcus, Jun 17 2017

A101514 Shifts one place left under the square binomial transform (A008459): a(0) = 1, a(n) = Sum_{k=0..n-1} C(n-1,k)^2*a(k).

Original entry on oeis.org

1, 1, 2, 7, 35, 236, 2037, 21695, 277966, 4198635, 73558135, 1475177880, 33495959399, 853167955357, 24182881926558, 757554068775721, 26068954296880361, 980202973852646786, 40079727064364154465, 1774594774575753650941, 84756211791797266285252
Offset: 0

Views

Author

Paul D. Hanna, Dec 06 2004

Keywords

Comments

Equals the main diagonal of symmetric square array A101515 shift right.
Empirical: a(n) = sum((number of standard immaculate tableaux of shape m)^2, m|=n), where this sum is over all compositions m of n > 0. - John M. Campbell, Jul 07 2017

Examples

			The binomial transform of the rows of the term-wise product of this sequence with the rows of Pascal's triangle produces the symmetric square array A101515, in which the main diagonal equals this sequence shift left:
BINOMIAL[1*1] = [(1),1,1,1,1,1,1,1,1,...],
BINOMIAL[1*1,1*1] = [1,(2),3,4,5,6,7,8,9,...],
BINOMIAL[1*1,1*2,2*1] = [1,3,(7),13,21,31,43,57,73,...],
BINOMIAL[1*1,1*3,2*3,7*1] = [1,4,13,(35),77,146,249,393,...],
BINOMIAL[1*1,1*4,2*6,7*4,35*1] = [1,5,21,77,(236),596,1290,...],
BINOMIAL[1*1,1*5,2*10,7*10,35*5,236*1] = [1,6,31,146,596,(2037),...],...
Thus the square binomial transform shifts this sequence one place left:
a(5) = 236 = 1^2*(1) + 4^2*(1) + 6^2*(2) + 4^2*(7) + 1^2*(35),
a(6) = 2037 = 1^2*(1) + 5^2*(1) + 10^2*(2) + 10^2*(7) + 5^2*(35) + 1^2*(236).
		

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; if n<=0 then 1 else
          add(binomial(n-1,k)^2 *a(k), k=0..n-1) fi
        end:
    seq(a(n), n=0..25);  # Alois P. Heinz, Sep 05 2008
  • Mathematica
    a[0] = 1;
    a[n_] := Sum[Binomial[n - 1, k]^2 a[k], {k, 0, n - 1}];
    Table[a[i], {i, 0, 20}] (* Philip B. Zhang, Oct 10 2014 *)
  • PARI
    {a(n)=if(n==0,1,sum(k=0,n-1,binomial(n-1,k)^2*a(k)))}
    for(n=0,20,print1(a(n),", "))

Formula

E.g.f. satisfies: B(x)/A(x) = Sum_{n>=0} x^n/n!^2 where A(x) = Sum_{n>=0} a(n)*x^n/n!^2 and B(x) = Sum_{n>=0} a(n+1)*x^n/n!^2. - Paul D. Hanna, Oct 10 2014

Extensions

Typo in definition corrected by Philip B. Zhang, Oct 10 2014

A102220 Triangular matrix, read by rows, equal to [2*I - A008459]^(-1), i.e., the matrix inverse of the difference of twice the identity matrix and the triangular matrix of squared binomial coefficients.

Original entry on oeis.org

1, 1, 1, 5, 4, 1, 55, 45, 9, 1, 1077, 880, 180, 16, 1, 32951, 26925, 5500, 500, 25, 1, 1451723, 1186236, 242325, 22000, 1125, 36, 1, 87054773, 71134427, 14531391, 1319325, 67375, 2205, 49, 1, 6818444405, 5571505472, 1138150832, 103334336, 5277300, 172480, 3920, 64, 1
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2004

Keywords

Comments

Column 0 forms A102221. Row sums form twice column 0 for n>0. Matrix logarithm is A102222.

Examples

			Rows begin:
[1],
[1,1],
[5,4,1],
[55,45,9,1],
[1077,880,180,16,1],
[32951,26925,5500,500,25,1],
[1451723,1186236,242325,22000,1125,36,1],...
and equal the term-by-term product of column 0
with the squared binomial coefficients (A008459):
[(1)1^2],
[(1)1^2,(1)1^2],
[(5)1^2,(1)2^2,(1)1^2],
[(55)1^2,(5)3^2,(1)3^2,(1)1^2],
[(1077)1^2,(55)4^2,(5)6^2,(1)4^2,(1)1^2],...
The matrix inverse is [2*I - A008459]:
[1],
[ -1,1],
[ -1,-4,1],
[ -1,-9,-9,1],
[ -1,-16,-36,-16,1],...
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1,
          add(b(n-i)*binomial(n, i)/i!, i=1..n))
        end:
    T:= (n, k)-> binomial(n, k)^2*b(n-k)*(n-k)!:
    seq(seq(T(n, k), k=0..n), n=0..10);  # Alois P. Heinz, Sep 10 2019
  • Mathematica
    nmax = 10;
    M = Inverse[2 IdentityMatrix[nmax+1] - Table[Binomial[n, k]^2, {n, 0, nmax}, {k, 0, nmax}]];
    T[n_, k_] := M[[n+1, k+1]];
    Table[T[n, k], {n, 0, nmax}, {k, 0, n}] // Flatten (* Jean-François Alcover, Dec 06 2019 *)
  • PARI
    {T(n,k)=(matrix(n+1,n+1,i,j,if(i==j,2,0)-binomial(i-1,j-1)^2)^-1)[n+1,k+1]}

Formula

T(n,k) = C(n,k)^2*A102221(n-k). T(n,0) = A102221(n). 2*A102221(n) = Sum_{k=0..n} T(n,k) for n>0.

A102222 Logarithm of triangular matrix A102220, which equals [2*I - A008459]^(-1).

Original entry on oeis.org

0, 1, 0, 3, 4, 0, 22, 27, 9, 0, 323, 352, 108, 16, 0, 7906, 8075, 2200, 300, 25, 0, 290262, 284616, 72675, 8800, 675, 36, 0, 14919430, 14222838, 3486546, 395675, 26950, 1323, 49, 0, 1022475715, 954843520, 227565408, 24793216, 1582700, 68992, 2352, 64, 0
Offset: 0

Views

Author

Paul D. Hanna, Dec 31 2004

Keywords

Comments

Column 0 forms A102223.

Examples

			Rows begin:
[0],
[1,0],
[3,4,0],
[22,27,9,0],
[323,352,108,16,0],
[7906,8075,2200,300,25,0],
[290262,284616,72675,8800,675,36,0],...
which equals the term-by-term product of column 0
with the squared binomial coefficients (A008459):
[(0)1^2],
[(1)1^2,(0)1^2],
[(3)1^2,(1)2^2,(0)1^2],
[(22)1^2,(3)3^2,(1)3^2,(0)1^2],
[(323)1^2,(22)4^2,(3)6^2,(1)4^2,(0)1^2],...
		

Crossrefs

Programs

  • PARI
    {T(n,k)=if(n
    				

Formula

T(n, k) = C(n, k)^2*A102223(n-k). T(n, 0) = A102223(n). T(n, n) = 0 for n>=0. [A102222] = Sum_{m=1..inf} [A008459 - I]^m/m.

A097085 Row sums of triangle A097084, in which the n-th diagonal equals the n-th row transformed by triangle A008459 (squared binomial coefficients).

Original entry on oeis.org

1, 2, 4, 10, 26, 70, 204, 618, 1908, 6010, 19316, 63034, 208210, 695594, 2346748, 7983450, 27364842, 94439262, 327922692, 1145029314, 4018618374, 14169874350, 50179643628, 178410716622, 636679332588, 2279906714610, 8190512723940
Offset: 0

Views

Author

Paul D. Hanna, Jul 23 2004

Keywords

Comments

a(n) is also the number of anagram compositions of 2n or of 2n+1. A composition of n is an ordered sequence of positive integers whose sum is n. An anagram composition of n can be divided into two consecutive subsequences with exactly the same parts, with a central part between the subsequences permitted. - Gregory L. Simay, Oct 30 2015

Examples

			[1,2,3,4][3,2,1,4] is an anagram composition of 20 enumerated by a(10), [3,2,1] 5 [2,1,3] is an anagram composition of 17 enumerated by a(8), [3467] 8 [7643] is an anagram composition of 48 enumerated by a(24). - _Gregory L. Simay_, Oct 30 2015
		

Crossrefs

Cf. A097084.
Cf. A263897. - Gregory L. Simay, Oct 30 2015

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(n=0, p!^2,
          `if`(i<1, 0, add(b(n-i*j, i-1, p+j)/j!^2, j=0..n/i)))
        end:
    a:= proc(n) option remember; b(n$2, 0)+`if`(n>0, a(n-1), 0) end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Oct 30 2015
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[n == 0, p!^2, If[i < 1, 0, Sum[b[n - i*j, i - 1, p + j]/j!^2, {j, 0, n/i}]]];
    a[n_] := a[n] = b[n, n, 0] + If[n > 0, a[n - 1], 0];
    Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jun 04 2018, after Alois P. Heinz *)

Formula

a(n) = Sum_{j=0..n} A263897(j). - Gregory L. Simay, Oct 30 2015

A097084 Triangle, read by rows, where the n-th diagonal equals the n-th row transformed by triangle A008459 (squared binomial coefficients).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 5, 1, 1, 4, 10, 10, 1, 1, 5, 18, 28, 17, 1, 1, 6, 27, 74, 69, 26, 1, 1, 7, 39, 137, 245, 151, 37, 1, 1, 8, 52, 236, 586, 676, 298, 50, 1, 1, 9, 68, 372, 1194, 2126, 1634, 540, 65, 1, 1, 10, 85, 552, 2322, 5152, 6620, 3578, 913, 82, 1, 1, 11, 105, 777, 3954, 12002, 19292, 18082, 7249, 1459, 101, 1
Offset: 0

Views

Author

Paul D. Hanna, Jul 23 2004

Keywords

Comments

Row sums form A097085.

Examples

			T(8,3) = 236 = (1)*1^2 + (5)*3^2 + (18)*3^2 + (28)*1^2
= Sum_{j=0..3} T(5,j)*C(3,j)^2.
Rows begin:
[1],
[1,1],
[1,2,1],
[1,3,5,1],
[1,4,10,10,1],
[1,5,18,28,17,1],
[1,6,27,74,69,26,1],
[1,7,39,137,245,151,37,1],
[1,8,52,236,586,676,298,50,1],...
		

Crossrefs

Programs

  • Maple
    T:= proc(n, k) option remember;
          `if`(n=k or k=0, 1, `if`(k<0 or k>n, 0,
           add(T(n-k, j)*binomial(k, j)^2, j=0..k)))
        end:
    seq(seq(T(n,k), k=0..n), n=0..12);  # Alois P. Heinz, Oct 30 2015
  • Mathematica
    T[, 0] = 1; T[n, n_] = 1; T[n_, k_] /; 0 < k < n := T[n, k] = Sum[T[n - k, j]*Binomial[k, j]^2, {j, 0, k}]; T[, ] = 0;
    Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, May 24 2016 *)
  • PARI
    T(n,k)=if(n
    				

Formula

T(n,k) = Sum_{j=0..k} T(n-k,j)*C(k,j)^2.
Showing 1-10 of 72 results. Next