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 1-10 of 13 results. Next

A220359 Decimal expansion of the root of the equation (1-r)^(2*r-1) = r^(2*r).

Original entry on oeis.org

7, 0, 3, 5, 0, 6, 0, 7, 6, 4, 3, 0, 6, 6, 2, 4, 3, 0, 9, 6, 9, 2, 9, 6, 6, 1, 6, 2, 1, 7, 7, 7, 0, 9, 5, 2, 1, 3, 2, 4, 6, 8, 4, 5, 7, 4, 2, 4, 2, 8, 1, 5, 5, 5, 5, 8, 6, 2, 1, 5, 7, 1, 6, 5, 1, 0, 5, 1, 2, 3, 0, 6, 0, 0, 3, 9, 9, 4, 0, 1, 4, 4, 9, 5, 2, 5, 4, 5, 6, 8, 0, 4, 6, 0, 5, 7, 3, 1, 5, 1, 9, 8, 5, 4, 4, 8, 3
Offset: 0

Views

Author

Vaclav Kotesovec, Dec 12 2012

Keywords

Comments

Constant is associated with A167008, A219206 and A219207.

Examples

			0.70350607643066243...
		

Crossrefs

Programs

  • Maple
    Digits:= 140:
    v:= convert(fsolve( (1-r)^(2*r-1) = r^(2*r), r=1/2), string):
    seq(parse(v[n+2]), n=0..120);  # Alois P. Heinz, Dec 12 2012
  • Mathematica
    RealDigits[r/.FindRoot[(1-r)^(2*r-1)==r^(2*r),{r,1/2}, WorkingPrecision->250], 10, 200][[1]]
  • PARI
    solve(x=.7,1,(1-x)^(2*x-1) - x^(2*x)) \\ Charles R Greathouse IV, Apr 25 2016

A096131 Sum of the terms of the n-th row of triangle pertaining to A096130.

Original entry on oeis.org

1, 7, 105, 2386, 71890, 2695652, 120907185, 6312179764, 375971507406, 25160695768715, 1869031937691061, 152603843369288819, 13584174777196666630, 1309317592648179024666, 135850890740575408906465
Offset: 1

Views

Author

Amarnath Murthy, Jul 04 2004

Keywords

Comments

The product of the terms of the n-th row is given by A034841.
Collection of partial binary matrices: 1 to n rows of length n and a total of n entries set to one in each partial matrix. - Olivier Gérard, Aug 08 2016

Examples

			From _Seiichi Manyama_, Aug 18 2018: (Start)
a(1) = (1/1!) * (1) = 1.
a(2) = (1/2!) * (1*2 + 3*4) = 7.
a(3) = (1/3!) * (1*2*3 + 4*5*6 + 7*8*9) = 105.
a(4) = (1/4!) * (1*2*3*4 + 5*6*7*8 + 9*10*11*12 + 13*14*15*16) = 2386. (End)
		

Crossrefs

Programs

  • GAP
    List(List([1..20],n->List([1..n],k->Binomial(k*n,n))),Sum); # Muniru A Asiru, Aug 12 2018
    
  • Maple
    A096130 := proc(n,k) binomial(k*n,n) ; end: A096131 := proc(n) local k; add( A096130(n,k),k=1..n) ; end: for n from 1 to 18 do printf("%d, ",A096131(n)) ; od ; # R. J. Mathar, Apr 30 2007
    seq(add((binomial(n*k,n)), k=0..n), n=1..15); # Zerinvary Lajos, Sep 16 2007
  • Mathematica
    Table[Sum[Binomial[k*n, n], {k, 0, n}], {n, 1, 20}] (* Vaclav Kotesovec, Jun 06 2013 *)
  • PARI
    a(n) = sum(k=1, n, binomial(k*n, n)); \\ Michel Marcus, Aug 20 2018

Formula

a(n) = Sum_{k=1..n} binomial(k*n, n). - Reinhard Zumkeller, Jan 09 2005
a(n) = (1/n!) * Sum_{j=1..n} Product_{i=n*(j-1)+1..n*j} i. - Reinhard Zumkeller, Jan 09 2005 [corrected by Seiichi Manyama, Aug 17 2018]
a(n) ~ exp(1)/(exp(1)-1) * binomial(n^2,n). - Vaclav Kotesovec, Jun 06 2013

Extensions

More terms from R. J. Mathar, Apr 30 2007
Edited by N. J. A. Sloane, Sep 06 2008 at the suggestion of R. J. Mathar

A226391 a(n) = Sum_{k=0..n} binomial(k*n, k).

Original entry on oeis.org

1, 2, 9, 103, 2073, 58481, 2101813, 91492906, 4671050401, 273437232283, 18046800575211, 1325445408799007, 107200425419863009, 9466283137384124247, 906151826270369213655, 93459630239922214535911, 10331984296666203358431361, 1218745075041575200343722415
Offset: 0

Views

Author

Vaclav Kotesovec, Jun 06 2013

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Binomial(n*j,j): j in [0..n]]): n in [0..30]]; // G. C. Greubel, Aug 31 2022
    
  • Mathematica
    Table[Sum[Binomial[k*n, k], {k, 0, n}], {n, 0, 20}]
  • Maxima
    A226391(n):=sum(binomial(k*n,k), k,0,n); makelist(A226391(n),n,0,30); /* Martin Ettl, Jun 06 2013 */
    
  • SageMath
    @CachedFunction
    def A226391(n): return sum(binomial(n*j, j) for j in (0..n))
    [A226391(n) for n in (0..30)] # G. C. Greubel, Aug 31 2022

Formula

a(n) ~ binomial(n^2, n).

A184731 a(n) = Sum_{k=0..n} C(n,k)^(k+1).

Original entry on oeis.org

1, 2, 6, 38, 490, 14152, 969444, 140621476, 46041241698, 36363843928316, 62022250535177416, 236043875222171125276, 2205302277098968939256248, 45728754995013679582534494332, 2070631745797418828103776968679204
Offset: 0

Views

Author

Paul D. Hanna, Jan 20 2011

Keywords

Examples

			The terms begin:
a(0) = 1;
a(1) = 1 + 1^2 = 2;
a(2) = 1 + 2^2 + 1^3 = 6;
a(3) = 1 + 3^2 + 3^3 + 1^4 = 38;
a(4) = 1 + 4^2 + 6^3 + 4^4 + 1^5 = 490;
a(5) = 1 + 5^2 + 10^3 + 10^4 + 5^5 + 1^6 = 14152.
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[n, k]^(k+1), {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Jan 29 2014 *)
  • PARI
    {a(n)=sum(k=0, n, binomial(n, k)^(k+1))}

Formula

Forms the logarithmic derivative of A184730 (ignoring the initial term).
Limit n->infinity a(n)^(1/n^2) = (1-r)^(-r/2) = 1.53362806511..., where r = 0.70350607643... (see A220359) is the root of the equation (1-r)^(2*r-1) = r^(2*r). - Vaclav Kotesovec, Jan 29 2014

A219206 Triangle, read by rows, where T(n,k) = binomial(n,k)^k for n>=0, k=0..n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 9, 1, 1, 4, 36, 64, 1, 1, 5, 100, 1000, 625, 1, 1, 6, 225, 8000, 50625, 7776, 1, 1, 7, 441, 42875, 1500625, 4084101, 117649, 1, 1, 8, 784, 175616, 24010000, 550731776, 481890304, 2097152, 1, 1, 9, 1296, 592704, 252047376, 31757969376, 351298031616, 78364164096, 43046721, 1
Offset: 0

Views

Author

Paul D. Hanna, Nov 14 2012

Keywords

Comments

Maximal term in row n is asymptotically in position k = r*n, where r = A220359 = 0.70350607643... is a root of the equation (1-r)^(2*r-1) = r^(2*r). - Vaclav Kotesovec, Nov 15 2012

Examples

			Triangle begins:
  1;
  1, 1;
  1, 2,   1;
  1, 3,   9,      1;
  1, 4,  36,     64,        1;
  1, 5, 100,   1000,      625,         1;
  1, 6, 225,   8000,    50625,      7776,         1;
  1, 7, 441,  42875,  1500625,   4084101,    117649,       1;
  1, 8, 784, 175616, 24010000, 550731776, 481890304, 2097152,  1;
  ...
		

Crossrefs

Cf. A167008 (row sums).

Programs

  • Haskell
    a219206 n k = a219206_tabl !! n !! k
    a219206_row n = a219206_tabl !! n
    a219206_tabl = zipWith (zipWith (^)) a007318_tabl a002262_tabl
    -- Reinhard Zumkeller, Feb 27 2015
  • PARI
    {T(n,k)=binomial(n,k)^k}
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print(""))
    

Formula

Row sums equal A167008.

A336214 a(n) = Sum_{k=0..n} k^n * binomial(n,k)^n, with a(0)=1.

Original entry on oeis.org

1, 1, 8, 270, 41984, 30706250, 94770093312, 1336016204844832, 76829717664330940416, 19838680914222199482800274, 20521247958509575370600000000000, 94285013320530947020636486516362047300, 1715947732437668013396578734960052732361179136
Offset: 0

Views

Author

Vaclav Kotesovec, Jul 12 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[{1, Table[Sum[k^n*Binomial[n, k]^n, {k, 1, n}], {n, 1, 15}]}]
  • PARI
    a(n) = if (n==0, 1, sum(k=0, n, k^n * binomial(n,k)^n)); \\ Michel Marcus, Jul 13 2020

Formula

a(n) ~ c * exp(-1/4) * 2^(n^2 - n/2) * n^(n/2) / Pi^(n/2), where c = Sum_{k = -infinity..infinity} exp(-2*k*(k-1)) = exp(1/2) * sqrt(Pi/2) * EllipticTheta(3, -Pi/2, exp(-Pi^2/2)) = 2.036643566277677716389243890291939003151565... if n is even and c = Sum_{k = -infinity..infinity} exp(-2*k^2 + 1/2) = exp(1/2) * EllipticTheta(3, 0, exp(-2)) = 2.096087809957308346119920713317351288828811... if n is odd.
a(n) = n^n * A328812(n-1) for n > 0. - Seiichi Manyama, Jul 15 2020

A362288 a(n) = Product_{k=0..n} binomial(n,k)^k.

Original entry on oeis.org

1, 1, 2, 27, 9216, 312500000, 4251528000000000, 95432797246104853383515625, 14719075154533285649961930052505436160000, 65577306173662530591576256095315195684570038194755952705536
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 14 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[Binomial[n, k]^k, {k, 0, n}], {n, 0, 10}]
    Table[(n!)^(n*(n+1)/2) / BarnesG[n+2]^n, {n, 0, 10}]
  • PARI
    a(n) = prod(k=0, n, binomial(n,k)^k); \\ Michel Marcus, Apr 14 2023

Formula

a(n) = Product_{k=0..n} n!^k / k!^n.
a(n) = A067055(n) / A255268(n).
a(n) ~ A^n * exp((6*n^3 + 12*n^2 - n - 1)/24) / ((2*Pi)^(n*(n+1)/4) * n^(n*(3*n+2)/12)), where A is the Glaisher-Kinkelin constant A074962.

A206154 a(n) = Sum_{k=0..n} binomial(n,k)^(k+2).

Original entry on oeis.org

1, 2, 10, 110, 2386, 125752, 14921404, 3697835668, 2223231412546, 3088517564289836, 9040739066816429380, 63462297965044771663708, 1064766030857977088480630740, 37863276208844960432962611293828, 3144384748384240804260912067907833280
Offset: 0

Views

Author

Paul D. Hanna, Feb 04 2012

Keywords

Comments

Ignoring initial term a(0), equals the logarithmic derivative of A206153.

Examples

			L.g.f.: L(x) = 2*x + 10*x^2/2 + 110*x^3/3 + 2386*x^4/4 + 125752*x^5/5 +...
where exponentiation yields A206151:
exp(L(x)) = 1 + 2*x + 7*x^2 + 48*x^3 + 693*x^4 + 26632*x^5 + 2542514*x^6 +...
Illustration of initial terms:
a(1) = 1^2 + 1^3 = 2;
a(2) = 1^2 + 2^3 + 1^4 = 10;
a(3) = 1^2 + 3^3 + 3^4 + 1^5 = 110;
a(4) = 1^2 + 4^3 + 6^4 + 4^5 + 1^6 = 2386;
a(5) = 1^2 + 5^3 + 10^4 + 10^5 + 5^6 + 1^7 = 125752; ...
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[n,k]^(k+2),{k,0,n}],{n,0,20}] (* Harvey P. Dale, Jan 16 2014 *)
  • PARI
    {a(n)=sum(k=0,n,binomial(n,k)^(k+2))}
    for(n=0,16,print1(a(n),", "))

Formula

Limit n->infinity a(n)^(1/n^2) = (1-r)^(-r/2) = 1.53362806511..., where r = 0.70350607643... (see A220359) is the root of the equation (1-r)^(2*r-1) = r^(2*r). - Vaclav Kotesovec, Jan 29 2014

A336213 a(n) = Sum_{k=0..n} k^k * binomial(n,k)^n, with a(0)=1.

Original entry on oeis.org

1, 2, 9, 163, 12609, 3906251, 4835455813, 23882051929709, 470073929716006913, 36867039626275056203923, 11562789460238169439667262501, 14393917436542502296957220221339601, 72060131612303615870363237649174605005057, 1424448870088911493303605765206905153730451241313
Offset: 0

Views

Author

Vaclav Kotesovec, Jul 12 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Table[1 + Sum[k^k * Binomial[n, k]^n, {k, 1, n}], {n, 0, 15}]
  • PARI
    a(n) = if (n==0, 1, sum(k=0, n, k^k * binomial(n,k)^n)); \\ Michel Marcus, Jul 13 2020

Formula

Let f(n) = exp(-1/4) * QPochhammer(exp(-4)) * 2^(n^2 - 1/4) * exp((3*log(n)^2 + 3*log(2)^2 + Pi^2 - 1)/24) * n^((1 - log(2))/4) / Pi^(n/2). For sufficiently large n 0.985... < a(n)/f(n) < 1.015...
a(n) ~ exp(-1/4) * QPochhammer(exp(-4)) * QPochhammer(-n*exp(-1)/2, exp(-4)) * 2^(n^2) / Pi^(n/2) if n is even and a(n) ~ exp(-1/4) * QPochhammer(exp(-4)) * QPochhammer(-n*exp(-3)/2, exp(-4)) * sqrt(n) * 2^(n^2 - 1/2) / Pi^(n/2) if n is odd.

A295611 a(n) = Sum_{k=0..n} (-1)^k*binomial(n,k)^k.

Original entry on oeis.org

1, 0, 0, 6, -30, -280, 35070, -2508268, -47103462, 241470400824, -256752145545390, 128291714550379292, 2203924344437376054780, -37693423679943326954848176, 485163732930867224220253809178, 27101025121379607823580070619517816
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 24 2017

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[(-1)^k Binomial[n, k]^k, {k, 0, n}], {n, 0, 15}]
    Table[Sum[(-1)^k (n!/(k! (n - k)!))^k, {k, 0, n}], {n, 0, 15}]
  • PARI
    a(n) = sum(k=0, n, (-1)^k*binomial(n,k)^k); \\ Michel Marcus, Nov 25 2017

Formula

a(n) = Sum_{k=0..n} (-1)^k*A219206(n,k).
Limit n->infinity |a(n)|^(1/n^2) = r^(r^2/(1-2*r)) = 1.533628065110458582053143..., where r = A220359 = 0.70350607643066243096929661621777... is the real root of the equation (1-r)^(2*r-1) = r^(2*r). - Vaclav Kotesovec, Nov 25 2017
Showing 1-10 of 13 results. Next