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 1-3 of 3 results.

A124320 Triangle read by rows: T(n,k) = k!*binomial(n+k-1,k) (n >= 0, 0 <= k <= n), rising factorial power, Pochhammer symbol.

Original entry on oeis.org

1, 1, 1, 1, 2, 6, 1, 3, 12, 60, 1, 4, 20, 120, 840, 1, 5, 30, 210, 1680, 15120, 1, 6, 42, 336, 3024, 30240, 332640, 1, 7, 56, 504, 5040, 55440, 665280, 8648640, 1, 8, 72, 720, 7920, 95040, 1235520, 17297280, 259459200, 1, 9, 90, 990, 11880, 154440, 2162160, 32432400, 518918400, 8821612800
Offset: 0

Views

Author

Emeric Deutsch, Oct 26 2006

Keywords

Comments

This is the Pochhammer function which is defined P(x,n) = x*(x+1)*...*(x+n-1). By convention P(0,0) = 1. Also known as the rising factorial power. - Peter Luschny, Jan 09 2011

Examples

			Triangle starts:
[0]  1;
[1]  1, 1;
[2]  1, 2,   6;
[3]  1, 3,  12,  60;
[4]  1, 4,  20, 120,  840;
[5]  1, 5,  30, 210, 1680, 15120;
[6]  1, 6,  42, 336, 3024, 30240, 332640;
[7]  1, 7,  56, 504, 5040, 55440, 665280, 8648640;
Array starts:
[0] 1,  1,   6,   60,   840,   15120,   332640,   8648640, ... A000407
[1] 1,  2,  12,  120,  1680,   30240,   665280,  17297280, ... A001813
[2] 1,  3,  20,  210,  3024,   55440,  1235520,  32432400, ... A006963
[3] 1,  4,  30,  336,  5040,   95040,  2162160,  57657600, ... A001761
[4] 1,  5,  42,  504,  7920,  154440,  3603600,  98017920, ... A102693
[5] 1,  6,  56,  720, 11880,  240240,  5765760, 160392960, ... A093197
[6] 1,  7,  72,  990, 17160,  360360,  8910720, 253955520, ... A203473
[7] 1,  8,  90, 1320, 24024,  524160, 13366080, 390700800, ...
[8] 1,  9, 110, 1716, 32760,  742560, 19535040, 586051200, ...
[9] 1, 10, 132, 2184, 43680, 1028160, 27907200, 859541760, ...
		

References

  • Ronald L. Graham, Donald E. Knuth and Oren Patashnik, Concrete Mathematics, Addison-Wesley, 1994.

Crossrefs

Cf. A123680 (row sums), A352601 (array main diagonal), A123680, A068424 (falling factorial power).

Programs

  • Maple
    T:=proc(n,k) if k<=n then binomial(n+k-1,k)*k! else 0 fi end: for n from 0 to 9 do seq(T(n,k),k=0..n) od; # yields sequence in triangular form
    A124320 := (n,k)-> `if`(n=0 and k=0,1,pochhammer(n,k)); seq(print(seq(A124320(n,k),k=0..n)),n=0..5); # Peter Luschny, Jan 09 2011
  • Mathematica
    Table[Pochhammer[n,k], {n,0,5},{k,0,n}]//Flatten (* Peter Luschny, Jan 09 2011 *)
  • PARI
    for(n=0,10, for(k=0,n, print1(if(n==0 && k==0, 1, (n+k-1)!/(n-1)!), ", "))) \\ G. C. Greubel, Nov 19 2017
  • Sage
    for n in (0..5) : [rising_factorial(n, k) for k in (0..n)] # Peter Luschny, Jan 09 2011
    

Formula

T(n,k) = GAMMA(n+k)/GAMMA(n) for n>0. - Peter Luschny, Jan 09 2011

A203472 a(n) = Product_{3 <= i < j <= n+2} (i + j).

Original entry on oeis.org

1, 7, 504, 498960, 8562153600, 3085457671296000, 27493649380770693120000, 6982164025191299372050022400000, 57286678477842677171688269225656320000000, 16987900892972660430046341200043192304533504000000000, 201504981205067832055356568153709798734509139298353152000000000000
Offset: 1

Views

Author

Clark Kimberling, Jan 02 2012

Keywords

Comments

Each term divides its successor, as in A203470. It is conjectured that each term is divisible by the corresponding superfactorial, A000178(n), as in A203474.

Crossrefs

Programs

  • Magma
    [(&*[(&*[i+j: i in [3..j]])/(2*j): j in [3..n+2]]): n in [1..20]]; // G. C. Greubel, Aug 26 2023
    
  • Maple
    a:= n-> mul(mul(i+j, i=3..j-1), j=4..n+2):
    seq(a(n), n=1..12);  # Alois P. Heinz, Jul 23 2017
  • Mathematica
    (* First program *)
    f[j_]:= j + 2;    z = 16;
    v[n_]:= Product[Product[f[k] + f[j], {j,k-1}], {k,2,n}]
    d[n_]:= Product[(i-1)!, {i,n}] (* A000178 *)
    Table[v[n], {n,z}]             (* A203472 *)
    Table[v[n+1]/v[n], {n,z-1}]    (* A203473 *)
    Table[v[n]/d[n], {n,20}]       (* A203474 *)
    (* Second program *)
    Table[(18*2^(n+2)^2/Pi^(n/2))*BarnesG[n+3]*BarnesG[n+7/2]/(BarnesG[n+ 6]*BarnesG[7/2]), {n,20}] (* G. C. Greubel, Aug 26 2023 *)
  • SageMath
    [product( gamma(2*j)/gamma(j+3) for j in range(3,n+3) ) for n in range(1,20)] # G. C. Greubel, Aug 26 2023

Formula

a(n) ~ 3*sqrt(A) * 2^(n^2 + 9*n/2 + 185/24) * n^(n^2/2 - n/2 - 179/24) / (Pi^(3/2) * exp(3*n^2/4 - n/2 + 1/24)), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Apr 09 2021
From G. C. Greubel, Aug 26 2023: (Start)
a(n) = Prod_{j=3..n+2} Prod_{i=3..j-1} (i + j).
a(n) = Prod_{j=3..n+2} Gamma(2*j)/Gamma(j+3).
a(n) = (18*2^(n+2)^2/Pi^(n/2))*BarnesG(n+3)*BarnesG(n+7/2)/(BarnesG(n+ 6)*BarnesG(7/2)). (End)

Extensions

Name edited by Alois P. Heinz, Jul 23 2017

A203474 a(n) = A203472(n) / A000178(n-1), where A000178 are the superfactorials.

Original entry on oeis.org

1, 7, 252, 41580, 29729700, 89278289100, 1104908105901600, 55674109640169820800, 11329124570678156834592000, 9258047307912482983660236480000, 30262334718212007877669234596364800000
Offset: 1

Views

Author

Clark Kimberling, Jan 02 2012

Keywords

Crossrefs

Programs

  • Magma
    [(&*[ Binomial(2*j+3, j+4): j in [1..n]]): n in [1..20]]; // G. C. Greubel, Aug 27 2023
    
  • Mathematica
    (* First program *)
    f[j_]:= j+2; z=16;
    v[n_]:= Product[Product[f[k] + f[j], {j,k-1}], {k,2,n}];
    d[n_]:= Product[(i-1)!, {i,n}]  (* A000178(n-1) *)
    Table[v[n], {n,z}]              (* A203472 *)
    Table[v[n+1]/v[n], {n,z-1}]     (* A203473 *)
    Table[v[n]/d[n], {n,20}]        (* A203474 *)
    (* Second program *)
    Table[Product[Binomial[2*j+3, j+4], {j,n}], {n,20}] (* G. C. Greubel, Aug 27 2023 *)
  • SageMath
    [product( binomial(2*j+5,j+5) for j in range(n) ) for n in range(1,20)] # G. C. Greubel, Aug 27 2023

Formula

a(n) ~ 3*A^(3/2) * 2^(n^2 + 4*n + 185/24) * exp(n/2 - 1/8) / (Pi^(n/2 + 3/2) * n^(n/2 + 59/8)), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Apr 09 2021
From G. C. Greubel, Aug 27 2023: (Start)
a(n) = Product_{j=1..n} binomial(2*j+3, j+4).
a(n) = (18*2^(n+2)^2/Pi^(n/2))*BarnesG(n+3)*BarnesG(n+7/2)/( BarnesG(n +1)*BarnesG(n+6)*BarnesG(7/2)). (End)

Extensions

Definition corrected by Vaclav Kotesovec, Apr 09 2021
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