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.

A253286 Square array read by upward antidiagonals, A(n,k) = Sum_{j=0..n} (n-j)!*C(n,n-j)* C(n-1,n-j)*k^j, for n>=0 and k>=0.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 3, 2, 1, 0, 13, 8, 3, 1, 0, 73, 44, 15, 4, 1, 0, 501, 304, 99, 24, 5, 1, 0, 4051, 2512, 801, 184, 35, 6, 1, 0, 37633, 24064, 7623, 1696, 305, 48, 7, 1, 0, 394353, 261536, 83079, 18144, 3145, 468, 63, 8, 1
Offset: 0

Views

Author

Peter Luschny, Mar 24 2015

Keywords

Examples

			Square array starts, A(n,k):
      1,       1,       1,       1,      1,      1,      1, ...  A000012
      0,       1,       2,       3,      4,      5,      6, ...  A001477
      0,       3,       8,      15,     24,     35,     48, ...  A005563
      0,      13,      44,      99,    184,    305,    468, ...  A226514
      0,      73,     304,     801,   1696,   3145,   5328, ...
      0,     501,    2512,    7623,  18144,  37225,  68976, ...
      0,    4051,   24064,   83079, 220096, 495475, 997056, ...
A000007, A000262, A052897, A255806, ...
Triangle starts, T(n, k) = A(n-k, k):
  1;
  0,   1;
  0,   1,   1;
  0,   3,   2,  1;
  0,  13,   8,  3,  1;
  0,  73,  44, 15,  4, 1;
  0, 501, 304, 99, 24, 5, 1;
		

Crossrefs

Main diagonal gives A293145.

Programs

  • Magma
    [k eq n select 1 else k*Factorial(n-k-1)*Evaluate(LaguerrePolynomial(n-k-1, 1), -k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 23 2021
  • Maple
    L := (n, k) -> (n-k)!*binomial(n,n-k)*binomial(n-1,n-k):
    A := (n, k) -> add(L(n,j)*k^j, j=0..n):
    # Alternatively:
    # A := (n, k) -> `if`(n=0,1, simplify(k*n!*hypergeom([1-n],[2],-k))):
    for n from 0 to 6 do lprint(seq(A(n,k), k=0..6)) od;
  • Mathematica
    A253286[n_, k_]:= If[k==n, 1, k*(n-k-1)!*LaguerreL[n-k-1, 1, -k]];
    Table[A253286[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 23 2021 *)
  • PARI
    {T(n, k) = if(n==0, 1, n!*sum(j=1, n, k^j*binomial(n-1, j-1)/j!))} \\ Seiichi Manyama, Feb 03 2021
    
  • PARI
    {T(n, k) = if(n<2, (k-1)*n+1, (2*n+k-2)*T(n-1, k)-(n-1)*(n-2)*T(n-2, k))} \\ Seiichi Manyama, Feb 03 2021
    
  • Sage
    flatten([[1 if k==n else k*factorial(n-k-1)*gen_laguerre(n-k-1, 1, -k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 23 2021
    

Formula

A(n,k) = k*n!*hypergeom([1-n],[2],-k) for n>=1 and 1 for n=0.
Row sums of triangle, Sum_{k=0..n} A(n-k, k) = 1 + A256325(n).
From Seiichi Manyama, Feb 03 2021: (Start)
E.g.f. of column k: exp(k*x/(1-x)).
T(n,k) = (2*n+k-2) * T(n-1,k) - (n-1) * (n-2) * T(n-2, k) for n > 1. (End)
From G. C. Greubel, Feb 23 2021: (Start)
A(n, k) = k*(n-1)!*LaguerreL(n-1, 1, -k) with A(0, k) = 1.
T(n, k) = k*(n-k-1)!*LaguerreL(n-k-1, 1, -k) with T(n, n) = 1.
T(n, 2) = A052897(n) = A086915(n)/2.
Sum_{k=0..n} T(n, k) = 1 + Sum_{k=0..n-1} (n-k-1)*k!*LaguerreL(k, 1, k-n+1). (End)

A293146 a(n) = n! * [x^n] exp(x/(1 - n*x)).

Original entry on oeis.org

1, 1, 5, 73, 2161, 108101, 8201701, 878797165, 126422091713, 23514740267401, 5492576235204901, 1574136880033408241, 543143967119720304625, 222106209904092987888013, 106221716052645457812866501, 58741017143127754662557082901, 37194600833984874761008613195521
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 01 2017

Keywords

Crossrefs

Programs

  • Maple
    S:=series(exp(x/(1-n*x)),x,31):
    seq(coeff(S,x,n)*n!,n=0..30); # Robert Israel, Oct 01 2017
  • Mathematica
    Table[n! SeriesCoefficient[Exp[x/(1 - n x)], {x, 0, n}], {n, 0, 16}]
    Join[{1}, Table[n! SeriesCoefficient[Product[Exp[n^k x^(k + 1)], {k, 0, n}], {x, 0, n}], {n, 1, 16}]]
    Join[{1}, Table[Sum[n^(n - k) n!/k! Binomial[n - 1, k - 1], {k, n}], {n, 1, 16}]]
    Join[{1}, Table[n^n (n - 1)! Hypergeometric1F1[1 - n, 2, -1/n], {n, 1, 16}]]
  • PARI
    {a(n) = if(n==0, 1, n!*sum(k=1, n, n^(n-k)*binomial(n-1, k-1)/k!))} \\ Seiichi Manyama, Feb 03 2021

Formula

a(n) ~ BesselI(1, 2) * sqrt(2*Pi) * n^(2*n-1/2) / exp(n). - Vaclav Kotesovec, Oct 01 2017
a(n) = n! * Sum_{k=1..n} n^(n-k) * binomial(n-1,k-1)/k! for n > 0. - Seiichi Manyama, Feb 03 2021

A317279 a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n-1,k-1)*n^k*n!/k!.

Original entry on oeis.org

1, 1, 0, -9, -32, 225, 3456, 2695, -433152, -4495743, 47872000, 1768142871, 6703534080, -597265448351, -11959736205312, 126058380654375, 9454322092343296, 84694164336894465, -5776865438988238848, -192541299662555831753, 1511905067561779200000, 243338391925401706938081, 3972949090873574466519040
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 25 2018

Keywords

Comments

a(n) is the n-th term of the inverse Lah transform of the powers of n.

Crossrefs

Programs

  • Magma
    l:= func< n, a, b | Evaluate(LaguerrePolynomial(n, a), b) >;
    [1]cat[(-1)^(n+1)*Factorial(n)*l(n-1,1,n): n in [1..30]]; // G. C. Greubel, Mar 09 2021
    
  • Maple
    A317279:= n -> `if`(n=0,1,(-1)^(n+1)*n!*simplify(LaguerreL(n-1,1,n), 'LaguerreL'));
    seq(A317279(n), n = 0..30); # G. C. Greubel, Mar 09 2021
  • Mathematica
    Join[{1}, Table[Sum[(-1)^(n-k) Binomial[n-1, k-1] n^k n!/k!, {k, n}], {n, 22}]]
    Table[n! SeriesCoefficient[Exp[n x/(1 + x)], {x, 0, n}], {n, 0, 22}]
    Table[n! SeriesCoefficient[Product[Exp[-n (-x)^k], {k, n}], {x, 0, n}], {n, 0, 22}]
    Join[{1}, Table[(-1)^(n+1) n n! Hypergeometric1F1[1-n, 2, n], {n, 22}]]
  • PARI
    a(n) = if (n==0, 1, (-1)^(n+1)*n!*pollaguerre(n-1, 1, n)); \\ Michel Marcus, Mar 10 2021
  • Sage
    [1]+[(-1)^(n+1)*factorial(n)*gen_laguerre(n-1,1,n) for n in (1..30)] # G. C. Greubel, Mar 09 2021
    

Formula

a(n) = n! * [x^n] exp(n*x/(1 + x)).
a(n) = n! * [x^n] Product_{k>=1} exp(-n*(-x)^k).
a(n) = (-1)^(n+1) * n * n! * Hypergeometric1F1([1-n], [2], n) with a(0) = 1.
a(n) = (-1)^(n+1) * n! * LaguerreL(n-1, 1, n) with a(0) = 1. - G. C. Greubel, Mar 09 2021

A317277 a(n) = Sum_{k=0..n} binomial(n-1,k-1)*k^n*n!/k!; a(0) = 1.

Original entry on oeis.org

1, 1, 6, 81, 1828, 60565, 2734926, 160109005, 11724156648, 1045312448841, 111114793839610, 13845807451708441, 1994597720747571468, 328351264019737949341, 61162428777982281583302, 12782305566531823350524805, 2975150384583838798131401296, 766253903501365584725344992529
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 25 2018

Keywords

Comments

a(n) is the n-th term of the Lah transform of the n-th powers.

Crossrefs

Programs

  • Magma
    [1]cat[(&+[Binomial(n-1,j-1)*Binomial(n,j)*Factorial(n-j)*j^n: j in [0..n]]): n in [1..30]]; // G. C. Greubel, Mar 09 2021
    
  • Maple
    A317277:= n-> `if`(n=0,1, add(binomial(n-1,j-1)*binomial(n,j)*(n-j)!*j^n, j=0..n)); seq(A317277(n), n=0..30); # G. C. Greubel, Mar 09 2021
  • Mathematica
    Join[{1}, Table[Sum[Binomial[n - 1, k - 1] k^n n!/k!, {k, n}], {n, 17}]]
    Join[{1}, Table[n! SeriesCoefficient[Sum[k^n (x/(1 - x))^k/k!, {k, n}], {x, 0, n}], {n, 17}]]
  • PARI
    a(n) = if (n==0, 1, sum(k=0, n, binomial(n-1, k-1)*k^n*n!/k!)); \\ Michel Marcus, Mar 10 2021; corrected Jun 15 2022
  • Sage
    [1]+[sum(binomial(n-1,j-1)*binomial(n,j)*factorial(n-j)*j^n for j in (0..n)) for n in (1..30)] # G. C. Greubel, Mar 09 2021
    

Formula

a(n) = n! * [x^n] Sum_{k>=0} k^n*(x/(1 - x))^k/k!.

Extensions

Name edited by Michel Marcus, Jun 15 2022
Showing 1-4 of 4 results.