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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A203529 a(n) = A203527(n)/A000178(n-1); A000178 = (superfactorials).

Original entry on oeis.org

1, 5, 175, 44100, 60913125, 427756329000, 20552836095792000, 6952965728817588480000, 11895516181976215338950400000, 99606443887767729350960121600000000, 5830034964946921746536425070101217280000000
Offset: 1

Views

Author

Clark Kimberling, Jan 03 2012

Keywords

Comments

It is conjectured that every term is an integer.

Crossrefs

Programs

  • Mathematica
    t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}];
    nonprime = Rest[Union[t]]              (* A018252 *)
    f[j_] := nonprime[[j]]; z = 20;
    v[n_] := Product[Product[f[k] + f[j], {j, 1, k - 1}], {k, 2, n}]
    d[n_] := Product[(i - 1)!, {i, 1, n}]  (* A000178 *)
    Table[v[n], {n, 1, z}]                 (* A203527 *)
    Table[v[n + 1]/v[n], {n, 1, z - 1}]    (* A203528 *)
    Table[v[n]/d[n], {n, 1, 20}]           (* A203529 *)

A203533 a(n) = A203530(n)/A000178(n-1); A000178 = (superfactorials).

Original entry on oeis.org

1, 10, 840, 464100, 1481407200, 32851686067200, 5186361382800998400, 4436556151786001058816000, 19667253420867342693731328000000, 605862171333980479840975997239296000000, 132207384898194165523202154782408753283072000000
Offset: 1

Views

Author

Clark Kimberling, Jan 03 2012

Keywords

Comments

It is conjectured that every term is an integer.

Crossrefs

Programs

  • Mathematica
    t = Table[If[PrimeQ[k], 0, k], {k, 1, 100}];
    composite = Rest[Rest[Union[t]]]       (* A002808 *)
    f[j_] := composite[[j]]; z = 20;
    v[n_] := Product[Product[f[k] + f[j], {j, 1, k - 1}], {k, 2, n}]
    d[n_] := Product[(i - 1)!, {i, 1, n}]  (* A000178 *)
    Table[v[n], {n, 1, z}]                 (* A203530 *)
    Table[v[n + 1]/v[n], {n, 1, z - 1}]    (* A203532 *)
    Table[v[n]/d[n], {n, 1, 20}]           (* A203533 *)

A219266 Logarithmic derivative of the superfactorials (A000178).

Original entry on oeis.org

1, 3, 31, 1103, 171311, 149089887, 877704854447, 40451674467223423, 16514355739866259408591, 66586047491662065505372477983, 2923692867015618804999172694908629103, 1527767556403309713534536695030930443376591295, 10306227067090276816548435451550663056418226402352755215
Offset: 1

Views

Author

Paul D. Hanna, Nov 16 2012

Keywords

Comments

Superfactorial A000178(n) equals the product of first n factorials.

Examples

			L.g.f.: L(x) = x + 3*x^2/2 + 31*x^3/3 + 1103*x^4/4 + 171311*x^5/5 +...
where
exp(L(x)) = 1 + x + 2*x^2 + 12*x^3 + 288*x^4 + 34560*x^5 + 24883200*x^6 + 125411328000*x^7 +...+ n!*(n-1)!*(n-2)!*...*3!*2!*1!*0!**x^n +...
		

Crossrefs

Programs

  • Mathematica
    nmax=15; Rest[CoefficientList[Series[Log[Sum[BarnesG[k+2]*x^k,{k,0,nmax}]],{x,0,nmax}],x] * Range[0,nmax]] (* Vaclav Kotesovec, Jul 10 2015 *)
  • PARI
    {a(n)=n*polcoeff(log(sum(k=0,n+1,prod(j=0,k,j!)*x^k)+x*O(x^n)),n)}
    for(n=1,21,print1(a(n),", "))

Formula

a(n) ~ n^(n^2/2 + n + 17/12) * (2*Pi)^((n+1)/2) / (A * exp(3*n^2/4 + n - 1/12)), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Jul 10 2015

A152690 Partial sums of superfactorials (A000178).

Original entry on oeis.org

1, 2, 4, 16, 304, 34864, 24918064, 125436246064, 5056710181206064, 1834938528961266006064, 6658608419043265483506006064, 265790273955000365854215115506006064
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    lst={};p0=1;s0=0;Do[p0*=a[n];s0+=p0;AppendTo[lst,s0],{n,0,4!}];lst
    s = 0; lst = {s}; Do[s += BarnesG[n]; AppendTo[lst, s], {n, 2, 13, 1}]; lst (* Zerinvary Lajos, Jul 16 2009 *)
    Table[Sum[BarnesG[k+1],{k,1,n}],{n,1,15}] (* Vaclav Kotesovec, Jul 10 2015 *)

Formula

G.f.: W(0)/(2-2*x) , where W(k) = 1 + 1/( 1 - x*(k+1)!/( x*(k+1)! + 1/W(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Aug 19 2013
a(n) ~ exp(1/12 - 3*n^2/4) * n^(n^2/2 - 1/12) * (2*Pi)^(n/2) / A, where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Jul 10 2015
a(n) = n! * G(n+1) + a(n-1), where G(z) is the Barnes G-function. - Daniel Suteu, Jul 23 2016

A156584 Triangle T(n,k) = SF(n+1)/(SF(n-k+1)*SF(k+1)) where SF(n) is the superfactorial A000178(n), read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 12, 12, 1, 1, 60, 240, 60, 1, 1, 360, 7200, 7200, 360, 1, 1, 2520, 302400, 1512000, 302400, 2520, 1, 1, 20160, 16934400, 508032000, 508032000, 16934400, 20160, 1, 1, 181440, 1219276800, 256048128000, 1536288768000, 256048128000, 1219276800, 181440, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 10 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,     1;
  1,     3,        1;
  1,    12,       12,         1;
  1,    60,      240,        60,         1;
  1,   360,     7200,      7200,       360,        1;
  1,  2520,   302400,   1512000,    302400,     2520,     1;
  1, 20160, 16934400, 508032000, 508032000, 16934400, 20160, 1;
		

Crossrefs

Cf. A007318 (m=0), this sequence (m=1), A156764 (m=3).
Cf. A009963.

Programs

  • Maple
    SF := n -> mul(j!, j=0..n): T := (n,k) -> SF(n-1)/(SF(n-k)*SF(k)):
    seq(print(seq(T(n,k),k=1..n-1)),n=0..9); # Peter Luschny, Jan 24 2015
  • Mathematica
    (* First program *)
    b[n_, k_]:= If[k==0, n!, Product[Sum[(-1)^(i+j)*(j+1)*StirlingS1[j-1, i]*(k+1)^i, {i, 0, j-1}], {j, 1, n}]];
    T[n_, k_, m_] = If[n==0, 1, b[n, m]/(b[k, m]*b[n-k, m])];
    Table[T[n, k, 1], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jun 20 2021 *)
    (* Second program *)
    f[n_, k_]:= If[k==0, n!, (-1)^n*(n+1)!*BarnesG[n+k+1]/(Gamma[k+1]^n*BarnesG[k+1])];
    T[n_, k_, m_]:= If[n==0, 1, f[n,m]/(f[k,m]*f[n-k,m])];
    Table[T[n,k,1], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jun 20 2021 *)
  • Sage
    def f(n,k): return factorial(n) if (k==0) else (-1)^n*factorial(n+1)*product( rising_factorial(k+1, j) for j in (0..n-1) )
    def T(n,k,m): return 1 if (n==0) else f(n,m)/(f(k,m)*f(n-k,m))
    flatten([[T(n,k,1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 21 2021

Formula

From G. C. Greubel, Jun 21 2021: (Start)
T(n, k) = BarnesG(n+3)/(BarnesG(k+3)*BarnesG(n-k+3)).
T(n, k, m) = f(n, m)/(f(k, m)*f(n-k, m)), with T(0, k, m) = 1, f(n, k) = (-1)^n*(n + 1)!*BarnesG(n+k+1)/(Gamma(k+1)^n*BarnesG(k+1)), f(n, 0) = n!, and m = 1. (End)

Extensions

New name and editing, Peter Luschny, Jan 24 2015

A173345 Number of trailing zeros of the superfactorial of n (A000178).

Original entry on oeis.org

0, 0, 0, 0, 1, 2, 3, 4, 5, 7, 9, 11, 13, 15, 18, 21, 24, 27, 30, 34, 38, 42, 46, 50, 56, 62, 68, 74, 80, 87, 94, 101, 108, 115, 123, 131, 139, 147, 155, 164, 173, 182, 191, 200, 210, 220, 230, 240, 250, 262, 274, 286, 298, 310, 323, 336, 349, 362, 375, 389, 403, 417
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := Sum[Z10[i], {i, n}]; Z10[n_]:= Floor[Sum[Floor[n/5^i], {i, 1, Floor[Log[5, n]]}]]; Join[{0},Table[a[n], {n, 2, 200}]]
    a[0] := 1; a[1] := 1; a[n_] := n!*a[n - 1];IntegerExponent[Table[a[n], {n, 1, 100}]] (* Stefano Spezia, Jan 26 2023 *)
  • PARI
    a(n)=my(t=0);sum(k=5,n,t+=valuation(k,5)) \\ Charles R Greathouse IV, Jun 10 2011

Formula

a(n) = Sum_{k=1..n} A027868(k). - Charles R Greathouse IV, Jun 10 2011

A193440 exp( Sum_{n>=1} x^n/G(n) ) = Sum_{n>=0} a(n)*x^n/G(n), where G(n) = Product_{k=0..n} k! = BarnesG(n+2), (see A000178).

Original entry on oeis.org

1, 1, 2, 9, 145, 10489, 4182481, 10893144241, 213590500341121, 35762619247862532481, 57146369032805384396332801, 963199581177063129894232882156801, 187554502919537918586035198740350553881601, 458564976873147078680542618033293809080455988300801
Offset: 0

Views

Author

Paul D. Hanna, Jul 25 2011

Keywords

Comments

Sum_{n>=0} a(n)/G(n) = 4.88825080515459884947818345139584332...

Examples

			A(x) = 1 + x + 2*x^2/2 + 9*x^3/12 + 145*x^4/288 + 10489*x^5/34560 + 4182481*x^6/24883200 + 10893144241*x^7/125411328000 +...+ a(n)*x^n/G(n) +...
where
log(A(x)) = x + x^2/2 + x^3/12 + x^4/288 + x^5/34560 + x^6/24883200 + x^7/125411328000 +...+ x^n/G(n) +...
and G(n) = 0!*1!*2!*3!*...*(n-1)!*n!.
		

Crossrefs

Cf. A000178.

Programs

  • Mathematica
    Table[BarnesG[n+2] * SeriesCoefficient[Exp[Sum[x^k/BarnesG[k+2], {k, 1, n}]], {x, 0, n}], {n, 0, 15}] (* Vaclav Kotesovec, Apr 03 2021 *)
  • PARI
    {a(n)=prod(k=1,n,k!)*polcoeff(exp(sum(m=1,n+1,x^m/prod(k=1,m,k!)+x*O(x^n))),n)}

Extensions

Definition corrected by Vaclav Kotesovec, Apr 03 2021

A193521 G.f.: A(x) = ( Sum_{n>=0} x^n/sf(n) )^3 where A(x) = Sum_{n>=0} a(n)*x^n/sf(n), and sf(n) = Product_{k=0..n} k! is the superfactorial of n (A000178).

Original entry on oeis.org

1, 3, 9, 51, 795, 43923, 10372323, 11996843043, 75315947454723, 2788806652875290883, 654625444656522114316803, 1045012738906587147509753740803, 12046169853230117709495421609499289603, 1053916215003128938522329980606467994425804803
Offset: 0

Views

Author

Paul D. Hanna, Jul 29 2011

Keywords

Examples

			Let F(x) = 1 + x + x^2/(1!*2!) + x^3/(1!*2!*3!) + x^4/(1!*2!*3!*4!) + ... + x^n/sf(n) + ...
then F(x)^3 = 1 + 3*x + 9*x^2/(1!*2!) + 51*x^3/(1!*2!*3!) + 795*x^4/(1!*2!*3!*4!) + 43923*x^5/(1!*2!*3!*4!*5!) + ... + a(n)*x^n/sf(n) + ...
		

Crossrefs

Programs

  • Magma
    A193521:= func< n | (&+[ A009963(n,k)*A193520(k): k in [0..n]]) >;
    [A193521(n): n in [0..20]]; // G. C. Greubel, Jan 05 2022
    
  • Mathematica
    a[n_]:= a[n]= Sum[BarnesG[n+2]/(BarnesG[j+2]*BarnesG[k-j+2]*BarnesG[n-k+2]), {k,0,n}, {j,0,k}];
    Table[a[n], {n, 0, 20}] (* G. C. Greubel, Jan 05 2022 *)
  • PARI
    {a(n) = prod(k=1,n,k!)*polcoeff((sum(m=0, n+1, x^m/prod(k=0, m, k!) + x*O(x^n))^3), n)}
    
  • Sage
    @CachedFunction
    def A009963(n,k): return product(factorial(n-j+1)/factorial(j) for j in (1..k))
    def A193521(n): return sum(sum(A009963(n,k)*A009963(k,j) for j in (0..k)) for k in (0..n))
    [A193521(n) for n in (0..20)] # G. C. Greubel, Jan 05 2022

Formula

From G. C. Greubel, Jan 05 2022: (Start)
a(n) = Sum_{k=0..n} Sum_{j=0..k} BarnesG(n+2)/(BarnesG(j+2)*BarnesG(k-j+2 )*BarnesG(n-k+2)).
a(n) = Sum_{k=0..n} A009963(n, k) * Sum_{j=0..k} A009963(k, j).
a(n) = Sum_{j=0..n} A009963(n, j)*A193520(j). (End)
a(n) ~ c(n) * A^2 * 3^(5/4 + n + n^2/6) * n^(-5/6 + n^2/3) / (2*Pi * exp(1/6 + n^2/2)), where c(n) = 1 if mod(n,3) = 0 and c(n) = 3^(4/3) / n^(1/3) if mod(n,3) = 1 or if mod(n,3) = 2, A = A074962 is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Aug 29 2023

A203313 a(n) = v(n)/A000178(n) where v=A203311 and A000178=(superfactorials).

Original entry on oeis.org

1, 1, 1, 4, 105, 46200, 730329600, 976445416826880, 253989513002664748108800, 30302715258078626805231995747942400, 3921367125196579314580337108803595790318851635200, 1315258359298445647817718300301463137710018409451973278413455360000
Offset: 1

Views

Author

Clark Kimberling, Jan 01 2012

Keywords

Crossrefs

Cf. A203311.

Programs

  • Mathematica
    f[j_] := Fibonacci[j + 1]; z = 15;
    v[n_] := Product[Product[f[k] - f[j], {j, 1, k - 1}], {k, 2, n}]
    d[n_] := Product[(i - 1)!, {i, 1, n}]
    Table[v[n], {n, 1, z}]               (* A203311 *)
    Table[v[n + 1]/v[n], {n, 1, z - 1}]  (* A123741 *)
    Table[v[n]/d[n], {n, 1, 13}]         (* A203313 *)
  • Python
    from sympy import fibonacci, factorial
    from operator import mul
    from functools import reduce
    def f(j): return fibonacci(j + 1)
    def v(n): return 1 if n==1 else reduce(mul, [reduce(mul, [f(k) - f(j) for j in range(1, k)]) for k in range(2, n + 1)])
    def d(n): return reduce(mul, [factorial(i - 1) for i in range(1, n + 1)])
    print([v(n)//d(n) for n in range(1, 14)]) # Indranil Ghosh, Jul 26 2017

A203467 a(n) = A203309(n)/A000178(n) where A000178 are superfactorials.

Original entry on oeis.org

1, 1, 2, 15, 630, 198450, 589396500, 19912024006875, 8969371213896843750, 61815874928487448987968750, 7358663747680777931818630148437500, 16862758880642741957030086746987589746093750
Offset: 0

Views

Author

Clark Kimberling, Jan 02 2012

Keywords

Crossrefs

Programs

  • Magma
    F:= Factorial; [1] cat [(&*[(F(2*k+2))/(2^k*F(k+2)): k in [0..n]]): n in [0..20]]; // G. C. Greubel, Aug 29 2023
    
  • Mathematica
    (* First program *)
    f[j_]:= j*(j+1)/2; z = 15;
    v[n_]:= Product[Product[f[k] - f[j], {j,k-1}], {k,2,n}]
    d[n_]:= Product[(i-1)!, {i,n}]
    Table[v[n], {n,0,z}]           (* A203309 *)
    Table[v[n+1]/v[n], {n,z}]      (* A203310 *)
    Table[v[n]/d[n], {n,0,12}]     (* A203467 *)
    (* Second program *)
    Table[Product[(2*k+2)!/(2^k*(k+2)!), {k,n-1}], {n,0,20}] (* G. C. Greubel, Aug 29 2023 *)
  • SageMath
    f=factorial; [product((f(2*j+2))/(2^j*f(j+2)) for j in range(n)) for n in range(21)] # G. C. Greubel, Aug 29 2023

Formula

From G. C. Greubel, Aug 29 2023: (Start)
a(n) = (2^(n+3)/Pi)^(n/2)*BarnesG(n+3/2)/(Gamma(n+ 2)*BarnesG(3/2)).
a(n) = (1/2)^binomial(n,2)*BarnesG(n+1)*Product_{k=2..n} binomial(2*k, k+1).
a(n) = Product_{k=1..n-1} (2*k+2)!/(2^k*(k+2)!). (End)
a(n) ~ sqrt(A/Pi) * 2^(n^2/2 + 2*n - 7/24) * n^(n^2/2 - n/2 - 35/24) / exp(3*n^2/4 - n/2 + 1/24), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Nov 19 2023

Extensions

Name edited by Michel Marcus, May 17 2019
a(0) = 1 prepended by G. C. Greubel, Aug 29 2023
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