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.

Previous Showing 21-29 of 29 results.

A340863 a(n) = n!*LaguerreL(n, -n^2).

Original entry on oeis.org

1, 2, 34, 1626, 151064, 23046370, 5228520912, 1651548277946, 692979602529664, 372856154213080674, 250277853396112428800, 205025892171407329263802, 201314381459222197472984064, 233396220344077025321595074306
Offset: 0

Views

Author

Seiichi Manyama, Feb 05 2021

Keywords

Crossrefs

Main diagonal of A338435.

Programs

  • Mathematica
    Table[n! * LaguerreL[n, -n^2], {n, 0, 13}] (* Amiram Eldar, Feb 05 2021 *)
  • PARI
    a(n) = sum(k=0, n, n^(2*k)*(n-k)!*binomial(n, k)^2);
    
  • PARI
    a(n) = n!*pollaguerre(n, 0, -n^2); \\ Michel Marcus, Feb 05 2021

Formula

a(n) = Sum_{k=0..n} n^(2*k) * (n-k)! * binomial(n,k)^2.
a(n) = n! * [x^n] exp(n^2 * x/(1-x))/(1-x).
a(n) = A289192(n,n^2).
a(n) ~ exp(1) * n^(2*n). - Vaclav Kotesovec, Feb 14 2021

A341197 a(n) = Sum_{k=0..n} k^n * (n-k)! * binomial(n,k)^2.

Original entry on oeis.org

1, 1, 8, 117, 2800, 97125, 4551876, 274975897, 20690260928, 1889451727497, 205192914235300, 26068434774065541, 3822244304373085680, 639508508456359098349, 120922358829574588363364, 25626415609908102483018225
Offset: 0

Views

Author

Seiichi Manyama, Feb 06 2021

Keywords

Crossrefs

Main diagonal of A341200.

Programs

  • Mathematica
    a[0] = 1; a[n_] := Sum[k^n * (n-k)! * Binomial[n, k]^2, {k, 0, n}]; Array[a, 16, 0] (* Amiram Eldar, Feb 06 2021 *)
  • PARI
    a(n) = sum(k=0, n, k^n*(n-k)!*binomial(n, k)^2);

A343847 T(n, k) = (n - k)! * [x^(n-k)] exp(k*x/(1 - x))/(1 - x). Triangle read by rows, T(n, k) for 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 6, 7, 3, 1, 24, 34, 14, 4, 1, 120, 209, 86, 23, 5, 1, 720, 1546, 648, 168, 34, 6, 1, 5040, 13327, 5752, 1473, 286, 47, 7, 1, 40320, 130922, 58576, 14988, 2840, 446, 62, 8, 1, 362880, 1441729, 671568, 173007, 32344, 4929, 654, 79, 9, 1
Offset: 0

Views

Author

Peter Luschny, May 07 2021

Keywords

Examples

			Triangle starts:
0:     1;
1:     1,      1;
2:     2,      2,     1;
3:     6,      7,     3,     1;
4:    24,     34,    14,     4,    1;
5:   120,    209,    86,    23,    5,   1;
6:   720,   1546,   648,   168,   34,   6,  1;
7:  5040,  13327,  5752,  1473,  286,  47,  7,  1;
8: 40320, 130922, 58576, 14988, 2840, 446, 62,  8,  1;
.
Array whose upward read antidiagonals are the rows of the triangle.
n\k   0       1       2        3        4         5        6
-----------------------------------------------------------------
0:    1,      1,      1,       1,       1,        1,        1, ...
1:    1,      2,      3,       4,       5,        6,        7, ...
2:    2,      7,     14,      23,      34,       47,       62, ...
3:    6,     34,     86,     168,     286,      446,      654, ...
4:   24,    209,    648,    1473,    2840,     4929,     7944, ...
5:  120,   1546,   5752,   14988,   32344,    61870,   108696, ...
6:  720,  13327,  58576,  173007,  414160,   866695,  1649232, ...
7: 5040, 130922, 671568, 2228544, 5876336, 13373190, 27422352, ...
		

Crossrefs

Row sums: A343848. T(2*n, n) = A277373(n). Variant: A289192.
Cf. A021009 (Laguerre polynomials), A344048.

Programs

  • Maple
    T := proc(n, k) option remember;
    if n = k then return 1 elif n = k+1 then return k+1 fi;
    (2*n-k-1)*T(n-1, k) - (n-k-1)^2*T(n-2, k) end:
    seq(print(seq(T(n ,k), k = 0..n)), n = 0..7);
  • Mathematica
    T[n_, k_] := (-1)^(n - k) HypergeometricU[k - n, 1, -k];
    Table[T[n, k], {n, 0, 9}, {k, 0, n}] // Flatten
    (* Alternative: *)
    TL[n_, k_] := (n - k)! LaguerreL[n - k, -k];
    Table[TL[n, k], {n, 0, 9}, {k, 0, n}] // Flatten
  • PARI
    T(n, k) = (n - k)!*sum(j=0, n - k, binomial(n - k, j) * k^j / j!)
    for(n=0, 9, for(k=0, n, print(T(n, k))))
    
  • SageMath
    # Columns of the array.
    def column(k, len):
        R. = PowerSeriesRing(QQ, default_prec=len)
        f = exp(k * x / (1 - x)) / (1 - x)
        return f.egf_to_ogf().list()
    for col in (0..6): print(column(col, 20))

Formula

T(n, k) = (-1)^(n - k)*U(k - n, 1, -k), where U is the Kummer U function.
T(n, k) = (n - k)! * L(n - k, -k), where L is the Laguerre polynomial function.
T(n, k) = (n - k)! * Sum_{j = 0..n - k} binomial(n - k, j) k^j / j!.
T(n, k) = (2*n-k-1)*T(n-1, k) - (n-k-1)^2*T(n-2, k) for n - k >= 2.

A344106 a(n) = n! * LaguerreL(n, -n+1).

Original entry on oeis.org

1, 1, 7, 86, 1473, 32344, 866695, 27422352, 1000578817, 41361536384, 1910451937671, 97512721964800, 5450486787062977, 331112639931669504, 21722219855305516807, 1530517712811373819904, 115269154497700063898625, 9241045907270523509112832, 785719407951447904088069383
Offset: 0

Views

Author

Vaclav Kotesovec, May 09 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Table[n!*LaguerreL[n, -n+1], {n, 0, 20}]
  • PARI
    a(n) = n!*subst(pollaguerre(n), x, 1-n); \\ Michel Marcus, May 09 2021

Formula

a(n) ~ exp((n-1)/phi - n) * phi^(2*n+1) * n^n / 5^(1/4), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio.
a(n) = Sum_{k=0..n} binomial(n, k)^2*(n - k)!*(n - 1)^k. - Peter Luschny, Dec 25 2021

A344107 a(n) = n! * LaguerreL(n, -n+2).

Original entry on oeis.org

1, 0, 2, 34, 648, 14988, 414160, 13373190, 495057024, 20686611736, 963532779264, 49510386761130, 2782552712473600, 169808382346687524, 11182975029610555392, 790535958617173397902, 59708339321680507207680, 4798728602043471360126000, 408910082803875174679773184
Offset: 0

Views

Author

Vaclav Kotesovec, May 09 2021

Keywords

Comments

In general, for fixed k>=0, n!*LaguerreL(n, -n+k) ~ exp((n-k)/phi - n) * phi^(2*n+1) * n^n / 5^(1/4).

Crossrefs

Programs

  • Mathematica
    Table[n!*LaguerreL[n, -n+2], {n, 0, 20}]
  • PARI
    a(n) = n!*subst(pollaguerre(n), x, 2-n); \\ Michel Marcus, May 09 2021

Formula

a(n) ~ exp((n-2)/phi - n) * phi^(2*n+1) * n^n / 5^(1/4), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio.

A277453 a(n) = Sum_{k=0..n} binomial(n,k) * 2^k * n^k * k!.

Original entry on oeis.org

1, 3, 41, 1531, 111393, 13262051, 2336744233, 570621092091, 184341785557121, 76092709735150723, 39064090158380196201, 24408768326642565035963, 18237590837527919131499041, 16056004231253610384348995811, 16448689708899063469247204152553
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 16 2016

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[{1, Table[Sum[Binomial[n, k]*2^k*n^k*k!, {k, 0, n}], {n, 1, 20}]}]

Formula

a(n) = exp(1/(2*n)) * 2^n * n^n * Gamma(n+1, 1/(2*n)).
a(n) ~ 2^n * n^n * n!.

A338435 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where T(n,k) = n!*LaguerreL(n, -k*n).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 14, 6, 1, 4, 34, 168, 24, 1, 5, 62, 654, 2840, 120, 1, 6, 98, 1626, 17688, 61870, 720, 1, 7, 142, 3246, 59928, 616120, 1649232, 5040, 1, 8, 194, 5676, 151064, 2844120, 26252496, 51988748, 40320, 1, 9, 254, 9078, 318744, 9052120, 165100752, 1322624016, 1891712384, 362880
Offset: 0

Views

Author

Seiichi Manyama, Feb 05 2021

Keywords

Examples

			Square array begins:
   1,    1,     1,     1,      1, ...
   1,    2,     3,     4,      5, ...
   2,   14,    34,    62,     98, ...
   6,  168,   654,  1626,   3246, ...
  24, 2840, 17688, 59928, 151064, ...
		

Crossrefs

Main diagonal gives A340863.
Cf. A021009, A289192 (n!*LaguerreL(n, -k)), A341014.

Programs

  • Mathematica
    T[n_, k_] := n! * LaguerreL[n, -k*n]; Table[T[k, n - k], {n, 0, 9}, {k, 0, n}] // Flatten (* Amiram Eldar, Feb 05 2021 *)
  • PARI
    T(n, k) = sum(j=0, n, (k*n)^j*(n-j)!*binomial(n, j)^2);
    
  • PARI
    T(n, k) = n!*pollaguerre(n, 0, -k*n); \\ Michel Marcus, Feb 05 2021

Formula

T(n,k) = Sum_{j=0..n} (k*n)^j * (n-j)! * binomial(n,j)^2.
T(n,k) = n! * [x^n] exp(k*n*x/(1-x))/(1-x).
T(n,k) = A289192(n,k*n).

A354943 a(n) = Sum_{k=0..n} binomial(n,k)^3 * k! * n^(n-k).

Original entry on oeis.org

1, 2, 22, 438, 12824, 496370, 23914512, 1379269094, 92667551104, 7108231236066, 612974464428800, 58702772664490262, 6181602019316333568, 709911177607125141362, 88301595129435811723264, 11825985945777638231211750, 1696696168760520436580974592, 259624546758869333450285984066
Offset: 0

Views

Author

Ilya Gutkovskiy, Jun 12 2022

Keywords

Crossrefs

Programs

  • Mathematica
    Unprotect[Power]; 0^0 = 1; Table[Sum[Binomial[n, k]^3 k! n^(n - k), {k, 0, n}], {n, 0, 17}]
    Unprotect[Power]; 0^0 = 1; Table[n!^3 SeriesCoefficient[BesselI[0, 2 Sqrt[x]] Sum[n^k x^k/k!^3, {k, 0, n}], {x, 0, n}], {n, 0, 17}]
  • PARI
    a(n) = sum(k=0, n, binomial(n,k)^3 * k! * n^(n-k)); \\ Michel Marcus, Jun 12 2022

Formula

a(n) = n!^3 * [x^n] BesselI(0,2*sqrt(x)) * Sum_{k>=0} n^k * x^k / k!^3.
a(n) ~ c * n^(n - 1/2) / (exp(r*n) * r^(2*n)), where r = (2 - 5*(2/(3*sqrt(69)-11))^(1/3) + ((3*sqrt(69)-11)/2)^(1/3))/3 = 0.430159709001946734... is the real root of the equation r^2 = (1-r)^3 and c = sqrt(138 + 2^(2/3)*(69*(8901 - 223*sqrt(69)))^(1/3) + 2^(2/3)*(69*(8901 + 223*sqrt(69)))^(1/3))/(2*sqrt(69*Pi)) = 0.684738330749970434111338151096549475398274404060139170789278633219363118... - Vaclav Kotesovec, Jul 01 2022, updated Mar 17 2024

A341056 a(n) = n! * [x^n] exp(x/(1 - n*x)) / (1 - x).

Original entry on oeis.org

1, 2, 9, 106, 2801, 132426, 9705577, 1015001954, 143392421601, 26298332570386, 6074043257989001, 1724846814877790682, 590605908915568818769, 239956225437223244619866, 114123836188192016600789481, 62808518765936960824453590226, 39603421893790601518269204039617
Offset: 0

Views

Author

Seiichi Manyama, Feb 04 2021

Keywords

Examples

			a(3) = 3! * (1 + 1/1! + 7/2! + 73/3!) = 106.
		

Crossrefs

Programs

  • Mathematica
    Table[n!*(1 + Sum[Sum[n^(j-k)*Binomial[j-1, k-1]/k!, {k, 1, j}], {j, 1, n}]), {n, 0, 20}] (* Vaclav Kotesovec, Feb 14 2021 *)
  • PARI
    {a(n) = n!*(1+sum(j=1, n, sum(k=1, j, n^(j-k)*binomial(j-1, k-1)/k!)))}

Formula

a(n) = n! * Sum_{k=0..n} A341033(k,n)/k! = n! * (1 + Sum_{j=1.. n} Sum_{k=1.. j} n^(j-k) * binomial(j-1,k-1)/k!).
a(n) ~ BesselI(1,2) * n! * n^(n-1). - Vaclav Kotesovec, Feb 14 2021
Previous Showing 21-29 of 29 results.