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 1-4 of 4 results.

A300484 a(n) = 2 * Integral_{t>=0} T_n(t/2+1) * exp(-t) * dt, n>=0, where T_n(x) is n-th Chebyshev polynomial of first kind.

Original entry on oeis.org

2, 3, 8, 29, 130, 697, 4376, 31607, 258690, 2368847, 24011832, 267025409, 3233119106, 42346123861, 596617706344, 8998126507307, 144651872924162, 2469279716419035, 44609768252582312, 850345380011532261, 17056474009400181122
Offset: 0

Views

Author

Max Alekseyev, Mar 06 2018

Keywords

Comments

For any integer n>=0, 2 * Integral_{t=-2..2} T_n(t/2)*exp(-t)*dt = 4 * Integral_{z=-1..1} T_n(z)*exp(-2*z)*dz = A102761(n)*exp(2) - a(n)*exp(-2).

Crossrefs

Row m=2 in A300480.
Row sums of A156995.

Programs

  • PARI
    { A300484(n) = if(n==0, return(2)); subst( serlaplace( 2*polchebyshev(n, 1, (x+2)/2)), x, 1); }

Formula

a(n) = Sum_{i=0..n} A127672(n,i) * A010842(i).
a(n) = A300480(2,n) = A300481(-2,n).
a(n) = Sum_{m=0..n} A156995(n,m) = 2*n*Sum_{m=0..n} binomial(2*n-m, m)*(n-m)!/(2*n-m).

A300480 Rectangular array read by antidiagonals: a(m,n) = 2 * Integral_{t>=0} T_n((t+m)/2)*exp(-t)*dt, m>=0, n>=0, where T_n(x) is n-th Chebyshev polynomial of first kind.

Original entry on oeis.org

2, 2, 1, 2, 2, 0, 2, 3, 3, 3, 2, 4, 8, 10, 18, 2, 5, 15, 29, 47, 95, 2, 6, 24, 66, 130, 256, 592, 2, 7, 35, 127, 327, 697, 1610, 4277, 2, 8, 48, 218, 722, 1838, 4376, 11628, 35010, 2, 9, 63, 345, 1423, 4459, 11770, 31607, 95167, 320589, 2, 10, 80, 514, 2562, 9820, 30248, 85634, 258690
Offset: 0

Views

Author

Max Alekseyev, Mar 06 2018

Keywords

Comments

a(m,n) is a polynomial in m of degree n.
For any integers m>=0, n>=0, 2 * Integral_{t=-m..m} T_n(t/2)*exp(-t)*dt = 4 * Integral_{z=-m/2..m/2} T_n(z)*exp(-2*z)*dz = A300481(m,n)*exp(m) - a(m,n)*exp(-m).

Examples

			Array starts with:
m=0: 2,  1,   0,    3,    18,     95,     592, ...
m=1: 2,  2,   3,   10,    47,    256,    1610, ...
m=2: 2,  3,   8,   29,   130,    697,    4376, ...
m=3: 2,  4,  15,   66,   327,   1838,   11770, ...
m=4: 2,  5,  24,  127,   722,   4459,   30248, ...
...
		

Crossrefs

Values for m<=0 are given in A300481.
Rows: A300482 (m=0), A300483 (m=1), A300484 (m=2), A300485 (m=-1), A102761 (m=-2).
Columns: A007395 (n=0), A000027 (n=1), A005563 (n=2), A084380 (n=3).
Cf. A000179 (almost row m=-2), A127672, A156995.

Programs

  • PARI
    { A300480(m,n) = if(n==0,return(2)); subst( serlaplace( 2*polchebyshev(n,1,(x+m)/2)), x, 1); }

Formula

a(m,n) = Sum_{i=0..n} A127672(n,i) * i! * Sum_{j=0..i} m^j/j!.
a(m,n) = Sum_{i=0..n} A127672(n,i) * A080955(m,i) = Sum_{i=0..n} A127672(n,i) * A089258(i,m).

A300481 Rectangular array read by antidiagonals: a(m,n) = 2 * Integral_{t>=0} T_n((t-m)/2)*exp(-t)*dt, m>=0, n>=0, where T_n(x) is n-th Chebyshev polynomial of first kind.

Original entry on oeis.org

2, 2, 1, 2, 0, 0, 2, -1, -1, 3, 2, -2, 0, 2, 18, 2, -3, 3, 1, 7, 95, 2, -4, 8, -6, 2, 34, 592, 2, -5, 15, -25, 15, 13, 218, 4277, 2, -6, 24, -62, 82, -28, 80, 1574, 35010, 2, -7, 35, -123, 263, -269, 106, 579, 12879, 320589
Offset: 0

Views

Author

Max Alekseyev, Mar 06 2018

Keywords

Comments

Although negative values of m are not present here or in A300480, the two arrays are connected with the formula: a(m,n) = A300480(-m,n). Thus, they essentially represent two "halves" of the same array indexed by integers m.
a(m,n) is a polynomial in m of degree n.
For any integers m>=0, n>=0, 2 * Integral_{t=-m..m} T_n(t/2)*exp(-t)*dt = 4 * Integral_{z=-m/2..m/2} T_n(z)*exp(-2*z)*dz = a(m,n)*exp(m) - A300480(m,n)*exp(-m).

Examples

			Array starts with:
m=0: 2,  1,  0,    3,   18,     95,    592, ...
m=1: 2,  0, -1,    2,    7,     34,    218, ...
m=2: 2, -1,  0,    1,    2,     13,     80, ...
m=3: 2, -2,  3,   -6,   15,    -28,    106, ...
m=4: 2, -3,  8,  -25,   82,   -269,    920, ...
...
		

Crossrefs

Values for m<=0 are given in A300480.
Rows: A300482 (m=0), A300485 (m=1), A102761 (m=2), A300483 (m=-1), A300484 (m=-2).
Columns (up to signs and offset): A007395 (n=0), A000027 (n=1), A005563 (n=2).
Cf. A000179 (almost row m=2), A127672, A156995.

Programs

Formula

a(m,n) = A300480(-m,n) = Sum_{i=0..n} A127672(n,i) * i! * Sum_{j=0..i} (-m)^j/j!.
a(m,n) = Sum_{i=0..n} A127672(n,i) * A292977(i,m).

A156996 Triangle T(n, k) = coefficients of p(n,x), where p(n,x) = Sum_{j=0..n} (2*n*(n-j)!/(2*n-j)) * binomial(2*n-j, j) * (x-1)^j and p(0,x) = 1, read by rows.

Original entry on oeis.org

1, -1, 2, 0, 0, 2, 1, 0, 3, 2, 2, 8, 4, 8, 2, 13, 30, 40, 20, 15, 2, 80, 192, 210, 152, 60, 24, 2, 579, 1344, 1477, 994, 469, 140, 35, 2, 4738, 10800, 11672, 7888, 3660, 1232, 280, 48, 2, 43387, 97434, 104256, 70152, 32958, 11268, 2856, 504, 63, 2, 439792, 976000, 1036050, 695760, 328920, 115056, 30300, 6000, 840, 80, 2
Offset: 0

Views

Author

Roger L. Bagula, Feb 20 2009

Keywords

Examples

			Triangle begins as:
       1;
      -1,      2;
       0,      0,       2;
       1,      0,       3,      2;
       2,      8,       4,      8,      2;
      13,     30,      40,     20,     15,      2;
      80,    192,     210,    152,     60,     24,     2;
     579,   1344,    1477,    994,    469,    140,    35,    2;
    4738,  10800,   11672,   7888,   3660,   1232,   280,   48,   2;
   43387,  97434,  104256,  70152,  32958,  11268,  2856,  504,  63,  2;
  439792, 976000, 1036050, 695760, 328920, 115056, 30300, 6000, 840, 80, 2;
		

References

  • J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, pp. 197-199

Crossrefs

Programs

  • Magma
    A156996:= func< n,k | n eq 0 select 1 else (&+[(-1)^(j-k)*(2*n*Factorial(n-j)/(2*n-j))*Binomial(j, k)*Binomial(2*n-j, j): j in [k..n]]) >;
    [A156996(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, May 14 2021
    
  • Mathematica
    (* first program *)
    Table[CoefficientList[If[n==0, 1, Sum[Binomial[2*n-k, k]*(n-k)!*(2*n/(2*n-k))*(x- 1)^k, {k,0,n}]], x], {n,0,12}]//Flatten
    (* Second program *)
    T[n_, k_]:= If[n==0, 1, Sum[(-1)^(j-k)*(2*n*(n-j)!/(2*n-j))*Binomial[j, k]*Binomial[2*n-j, j], {j,k,n}]];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, May 14 2021 *)
  • Sage
    def A156996(n,k): return 1 if (n==0) else sum( (-1)^(j-k)*(2*n*factorial(n-j)/(2*n-j))*binomial(j, k)*binomial(2*n-j, j) for j in (k..n) )
    flatten([[A156996(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 14 2021

Formula

T(n, k) = coefficients of p(n,x), where p(n,x) = Sum_{j=0..n} (2*n*(n-j)!/(2*n-j)) * binomial(2*n-j, j) * (x-1)^j and p(0,x) = 1.
Sum_{k=0..n} T(n, k) = n!.
From G. C. Greubel, May 14 2021: (Start)
T(n, 0) = A000179(n).
T(n, k) = Sum_{j=k..n} (-1)^(j+k)*(2*n*(n-j)!/(2*n-j))*binomial(j, k)*binomial(2*n-j, j), with T(0, k) = 1. (End)

Extensions

Edited by G. C. Greubel, May 14 2021
Showing 1-4 of 4 results.