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.

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A323717 a(n) = Product_{k=0..n} (n! + k!).

Original entry on oeis.org

2, 4, 36, 4704, 23400000, 7778123781120, 245221791787632844800, 980866487456532919096049664000, 647456833933936977045736601678008811520000, 89423837415458106416291101560480526982914768896000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Jan 25 2019

Keywords

Crossrefs

Programs

  • Magma
    F:= Factorial; [(&*[F(n) + F(j): j in [0..n]]): n in [0..20]]; // G. C. Greubel, Aug 30 2023
    
  • Mathematica
    Table[Product[n!+k!, {k, 0, n}], {n, 0, 10}]
  • SageMath
    f=factorial; [product(f(n) + f(k) for k in range(n+1)) for n in range(21)] # G. C. Greubel, Aug 30 2023

Formula

a(n) ~ 2^((n+3)/2) * Pi^((n+1)/2) * n^((n+1)*(2*n+1)/2) / exp(n^2 + n - 1/12).
a(n) ~ 2 * (n!)^(n+1). - Vaclav Kotesovec, Mar 28 2019

A336247 a(n) = (n!)^n * Sum_{k=0..n} 1 / (k!)^n.

Original entry on oeis.org

1, 2, 9, 460, 684545, 50547203126, 280807908057046657, 165858480204085842350156792, 13997217669604247492958380810030809089, 218434494471443385260764665498960241287478619115850, 792268399795067334328715213043856435592857850955707257780000000001
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 14 2020

Keywords

Crossrefs

Main diagonal of A343863.

Programs

  • Mathematica
    Table[(n!)^n Sum[1/(k!)^n, {k, 0, n}], {n, 0, 10}]
  • PARI
    a(n) = (n!)^n * sum(k=0, n, 1/(k!)^n); \\ Michel Marcus, Jul 14 2020

A060943 a(n) = n!^n * Sum_{k=1..n} 1/k^n.

Original entry on oeis.org

1, 5, 251, 357904, 25795462624, 141727869124448256, 83296040059942781485105152, 7013444132843374500928464765799366656, 109329825340451764123791003609208862665771818418176, 396334659032531033249146049131230887376087800711479296000000000000
Offset: 1

Views

Author

Leroy Quet, May 07 2001

Keywords

Examples

			a(3) = 6^3 *(1 + 1/2^3 + 1/3^3) = 251.
		

Crossrefs

Cf. A036740.
Main diagonal of A291556.

Programs

  • Magma
    [(Factorial(n))^n*(&+[1/j^n: j in [1..n]]): n in [1..15]]; // G. C. Greubel, Apr 09 2021
    
  • Maple
    A060943:= n-> (n!)^n*add(1/j^n, j=1..n); seq(A060943(n), n=1..15); # G. C. Greubel, Apr 09 2021
  • Mathematica
    Table[(n!)^n * Sum[1/i^n, {i, 1, n}], {n, 1, 10}] (* Vaclav Kotesovec, Aug 27 2017 *)
  • PARI
    { default(realprecision, 100); for (n=1, 30, write("b060943.txt", n, " ", n!^n * sum(k=1, n, 1/k^n)); ) } \\ Harry J. Smith, Jul 14 2009
    
  • Sage
    [(factorial(n))^n*sum(1/j^n for j in (1..n)) for n in (1..15)] # G. C. Greubel, Apr 09 2021

Formula

a(n) ~ 2^(n/2) * Pi^(n/2) * n^(n*(2*n+1)/2) / exp(n^2 - 1/12). - Vaclav Kotesovec, Aug 27 2017
a(n) = (n!)^n * [x^n] PolyLog(n,x)/(1 - x), where PolyLog() is the polylogarithm function. - Ilya Gutkovskiy, Nov 27 2017

A134373 a(n) = ((2n)!)^3.

Original entry on oeis.org

1, 8, 13824, 373248000, 65548320768000, 47784725839872000000, 109903340320478724096000000, 662559760549147780765974528000000, 9159226129831418921308831875072000000000, 262435789155225791087396177124997988352000000000
Offset: 0

Views

Author

Artur Jasinski, Oct 22 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[((2n)!)^(3), {n, 0, 10}]
    ((2*Range[0, 10])!)^3 (* Harvey P. Dale, Jul 25 2016 *)
  • Sage
    [factorial(2*n)**3 for n in range(0,9)] # Stefano Spezia, Apr 22 2025

Extensions

Definition corrected by Harvey P. Dale, Jul 25 2016

A261490 The total element sum of the n-fold f transform applied to the length n sequence of 1's. And f returns a sorted result after multiplying the elements in its input sequence with 1, 2, 3,... in descending size order.

Original entry on oeis.org

0, 1, 4, 19, 100, 633, 4626, 37878, 348224, 3542952, 39339852, 478962252, 6289532928, 89038853856, 1346224983936, 21729308136720, 371924399416320, 6740200653419520, 128878557725067264, 2598800542616444724, 54986036469506668800, 1217069235297874269792
Offset: 0

Views

Author

Alois P. Heinz, Aug 21 2015

Keywords

Crossrefs

Main diagonal of A166278.
Cf. A031971 (for ascending sort), A036740 (when sum is replaced by product).

Programs

  • Maple
    f:= l-> sort([seq(sort(l, `>`)[i]*i, i=1..nops(l))]):
    a:= n-> add(i, i=(f@@n)([1$n])):
    seq(a(n), n=0..35);

A343899 a(n) = Sum_{k=0..n} (k!)^k * binomial(n,k).

Original entry on oeis.org

1, 2, 7, 232, 332669, 24884861086, 139314218808181027, 82606412229102532926819812, 6984964247802365417561163907914436537, 109110688415634181158572146813823590758078301022074, 395940866122426284350759726810156652343313286283891529199276099071
Offset: 0

Views

Author

Seiichi Manyama, May 03 2021

Keywords

Comments

Binomial transform of (n!)^n.

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[(k!)^k * Binomial[n, k], {k, 0, n}]; Array[a, 11, 0] (* Amiram Eldar, May 05 2021 *)
  • PARI
    a(n) = sum(k=0, n, k!^k*binomial(n, k));
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k!*x)^k/(1-x)^(k+1)))
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x)*sum(k=0, N, k!^(k-1)*x^k)))

Formula

G.f.: Sum_{k>=0} (k! * x)^k/(1 - x)^(k+1).
E.g.f.: exp(x) * Sum_{k>=0} (k!)^(k-1) * x^k.

A343900 a(n) = Sum_{k=0..n} (k!)^(k+1) * binomial(n,k).

Original entry on oeis.org

1, 2, 11, 1324, 7967861, 2986023826166, 100306147958903465407, 416336313421816733159702737376, 281633758448076539969292901914477101456489, 39594086612245054028213574779019294652734771094507399786
Offset: 0

Views

Author

Seiichi Manyama, May 03 2021

Keywords

Comments

Binomial transform of (n!)^(n+1).

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[(k!)^(k+1) * Binomial[n, k], {k, 0, n}]; Array[a, 10, 0] (* Amiram Eldar, May 05 2021 *)
  • PARI
    a(n) = sum(k=0, n, k!^(k+1)*binomial(n, k));
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, k!^(k+1)*x^k/(1-x)^(k+1)))
    
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x)*sum(k=0, N, (k!*x)^k)))

Formula

G.f.: Sum_{k>=0} (k!)^(k+1) * x^k/(1 - x)^(k+1).
E.g.f.: exp(x) * Sum_{k>=0} (k! * x)^k.

A036739 a(n) = (n!)^n+1.

Original entry on oeis.org

2, 2, 5, 217, 331777, 24883200001, 139314069504000001, 82606411253903523840000001, 6984964247141514123629140377600000001, 109110688415571316480344899355894085582848000000001, 395940866122425193243875570782668457763038822400000000000000000001
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

Formula

a(n) ~ (2*Pi)^(n/2) * n^(n^2 + n/2) / exp(n^2 - 1/12). - Vaclav Kotesovec, Mar 19 2018

Extensions

One more term from Harvey P. Dale, Apr 10 2012

A299036 a(n) = [x^n] Product_{k=1..n} 1/(1-k!*x).

Original entry on oeis.org

1, 1, 7, 381, 502789, 33572762781, 175123095782787181, 99374457734129265819664221, 8158897372191288496224413025490409437, 124778468912108975502836576328262294089846582756189
Offset: 0

Views

Author

Seiichi Manyama, Feb 01 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[1/(1 - k!*x), {k, 1, n}], {x, 0, n}], {n, 0, 12}] (* Vaclav Kotesovec, Feb 02 2018 *)

Formula

From Vaclav Kotesovec, Feb 02 2018: (Start)
a(n) ~ (n!)^n.
a(n) ~ 2^(n/2) * Pi^(n/2) * n^(n*(2*n+1)/2) / exp(n^2 - 1/12). (End)

A100685 Powers of factorials A000142.

Original entry on oeis.org

1, 2, 4, 6, 8, 16, 24, 32, 36, 64, 120, 128, 216, 256, 512, 576, 720, 1024, 1296, 2048, 4096, 5040, 7776, 8192, 13824, 14400, 16384, 32768, 40320, 46656, 65536, 131072, 262144, 279936, 331776, 362880, 518400, 524288, 1048576, 1679616, 1728000
Offset: 1

Views

Author

Kyle Schalm and Jonathan Sondow, Dec 08 2004

Keywords

Comments

Subsequence of A001013. Supersequence of A036740 without its first term.
Supersequence also of A046882 and A055209 without their first terms. - Jonathan Sondow and Robert G. Wilson v, Dec 19 2004

Examples

			24 = (4!)^1 and 36 = (3!)^2.
		

Crossrefs

Cf. also A046882 and A055209.
Subsequences: A000079, A000400, A009968.

Programs

  • Mathematica
    With[{ln = Log[10!]}, Table[With[{f = m!}, Table[f^j, {j, 0, Floor[ln/Log[f]]}]], {m, 2, 10}]] //Flatten //Union

Formula

Sum_{n>=1} 1/a(n) = 1 + A331373. - Amiram Eldar, Nov 21 2021
Previous Showing 21-30 of 58 results. Next