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 1-7 of 7 results.

A005810 a(n) = binomial(4n,n).

Original entry on oeis.org

1, 4, 28, 220, 1820, 15504, 134596, 1184040, 10518300, 94143280, 847660528, 7669339132, 69668534468, 635013559600, 5804731963800, 53194089192720, 488526937079580, 4495151581425648, 41432089765583440, 382460951663844400
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

Start off with 0 balls in a box. Find the number of ways you can throw 3 balls back out. Then continue to throw 4 balls into the box after each stage. (I.e., the first stage is 0. Then at the next stage there are 4 ways to throw 3 balls back out.) - Ruppi Rana (ruppirana007(AT)hotmail.com), Mar 03 2004
Central coefficients of A094527. - Paul Barry, Mar 08 2011
This is the case m = 2n in Catalan's formula (2m)!*(2n)!/(m!*(m+n)!*n!) - see Umberto Scarpis in References. - Bruno Berselli, Apr 27 2012
A generating function in terms of a (labyrinthine) solution to a depressed quartic equation is given in the Copeland link for signed A005810. - Tom Copeland, Oct 10 2012
Conjecture: a(n) == 4 (mod n^3) iff n is prime. - Gary Detlefs, Apr 03 2013
For prime p, the congruence a(p) = binomial(4*p,p) = 4 (mod p^3) is a known generalization of Wolstenholme's theorem. See Mestrovic, Section 6, equation 35. - Peter Bala, Dec 28 2014

Examples

			G.f. = 1 + 4*x + 28*x^2 + 220*x^3 + 1820*x^4 + 15504*x^5 + 134596*x^6 + ...

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 828.
  • Umberto Scarpis, Sui numeri primi e sui problemi dell'analisi indeterminata in Questioni riguardanti le matematiche elementari, Nicola Zanichelli Editore (1924-1927, third Edition), page 11.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Row 4 of A060539.
binomial(k*n,n): A000984 (k = 2), A005809 (k = 3), A001449 (k = 5), A004355 (k = 6), A004368 (k = 7), A004381 (k = 8), A169958 - A169961 (k = 9 thru 12).
Cf. A007318, A182400, A262261, A378806, A378807.

Programs

Formula

a(n) is asymptotic to c*(256/27)^n/sqrt(n) with c = sqrt(2 / (3 Pi)) = 0.460658865961780639... - Benoit Cloitre, Jan 26 2003; corrected by Charles R Greathouse IV, Dec 14 2006
a(n) = Sum_{k=0..2n} binomial(2n,k) * binomial(2n,k-n). - Paul Barry, Mar 08 2011
G.f.: g/(4-3*g) where g = 1+x*g^4 is the g.f. of A002293. - Mark van Hoeij, Nov 11 2011
D-finite with recurrence: 3*n*(3*n-1)*(3*n-2)*a(n) - 8*(4*n-3)*(2*n-1)*(4*n-1)*a(n-1) = 0. - R. J. Mathar, Dec 02 2012
a(n) = binomial(4*n,n-1)*(3*n+1)/n. - Gary Detlefs, Apr 03 2013
a(n) = C(4*n-1,n-1)*C(16*n^2,2)/(3*n*C(4*n+1,3)), n>0. - Gary Detlefs, Jan 02 2014
a(n) = Sum_{i,j,k = 0..n} binomial(n,i)*binomial(n,j)*binomial(n,k)* binomial(n,i+j+k). - Peter Bala, Dec 28 2014
a(n) = GegenbauerC(n, -2*n, -1). - Peter Luschny, May 07 2016
From Ilya Gutkovskiy, Nov 22 2016: (Start)
O.g.f.: 3F2(1/4,1/2,3/4; 1/3,2/3; 256*x/27).
E.g.f.: 3F3(1/4,1/2,3/4; 1/3,2/3,1; 256*x/27). (End)
a(n) = hypergeom([-3*n, -1*n], [1], 1). - Peter Luschny, Mar 19 2018
RHS of the identity Sum_{k = 0..2*n} (-1)^(n+k)*binomial(4*n, k)* binomial(4*n, 2*n-k) = binomial(4*n,n). - Peter Bala, Oct 07 2021
From Peter Bala, Feb 20 2022: (Start)
The o.g.f. A(x) satisfies the differential equation
(-256*x^3 + 27*x^2)*A(x)''' + (-1152*x^2 + 54*x)*A(x)'' + (-816*x + 6)*A(x)' - 24*A(x) = 0 with A(0) = 1, A'(0) = 4 and A''(0) = 56.
Algebraic equation: (1 - A(x))*(1 + 3*A(x))^3 + 256*x*A(x)^4 = 0.
Sum_{n >= 1} a(n)*( x*(3*x + 4)^3/(256*(1 + x)^4) )^n = x. (End)
From Amiram Eldar, Dec 07 2024: (Start)
Sum_{n>=1} 1/a(n) = A378806.
Sum_{n>=1} (-1)^n/a(n) = A378807. (End)
From Peter Bala, Jun 29 2025: (Start)
a(n) = (1/8)^n * Sum_{k = n..4*n} binomial(k, n) * binomial(4*n, k).
Sum_{n >= 0 } a(n)*(1/128)^n = (1/5)*(sqrt(2) + sqrt(7 + 5*sqrt(2))). (End)
From Seiichi Manyama, Aug 16 2025: (Start)
a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(4*n+1,k).
G.f.: 1/(1 - 4*x*g^3) where g = 1+x*g^4 is the g.f. of A002293. (End)

Extensions

More terms from Henry Bottomley, Oct 06 2000
Corrected by T. D. Noe, Jan 16 2007

A268196 a(n) = Product_{k=0..n} binomial(3*k,k).

Original entry on oeis.org

1, 3, 45, 3780, 1871100, 5618913300, 104309506501200, 12129109415959536000, 8920608231265175901456000, 41809329673499408044341517200000, 1256161937180234817183361549396758000000, 243113461110708695347467432844366521953760000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 16 2016

Keywords

Links

Crossrefs

Cf. A001142, A005809, A007685, A086205, A112332, A268504, A262261.

Programs

  • Mathematica
    Table[Product[Binomial[3k,k],{k,0,n}],{n,0,12}]
FoldList[Times,Table[Binomial[3n,n],{n,0,15}]] (* Harvey P. Dale, Apr 23 2018 *)

Formula

a(n) = A^(7/6) * Gamma(1/3)^(1/3) * 3^(3*n^2/2 + 2*n + 11/36)* BarnesG(n + 4/3) * BarnesG(n + 5/3) / (exp(7/72) * 2^(n^2 + 2*n + 5/8) * Pi^(n/2 + 5/12) * BarnesG(n + 3/2) * BarnesG(n + 2)), where A = A074962 is the Glaisher-Kinkelin constant.
a(n) ~ A^(7/6) * Gamma(1/3)^(1/3) * 3^(11/36 + 2*n + 3*n^2/2) * exp(n/2 - 7/72) / (2^(n^2 + 2*n + 7/8) * Pi^(n/2 + 2/3) * n^(n/2 + 25/72)), where A = A074962 is the Glaisher-Kinkelin constant.
a(n) = A268504(n) / (A000178(n) * A098694(n)).

A272094 a(n) = Product_{k=0..n} binomial(k^2,k).

Original entry on oeis.org

1, 1, 6, 504, 917280, 48735086400, 94925811409228800, 8154182636726616909619200, 36091760791026276649159689107865600, 9415901310649088228943246038670339934863360000, 162992165498634702043940163611264755298214594247272038400000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 20 2016

Keywords

Crossrefs

Cf. A255322, A272093, A272095.
Cf. A000178, A098694, A268196, A262261.

Programs

  • Mathematica
    Table[Product[Binomial[k^2, k], {k, 0, n}], {n, 0, 10}]

Formula

a(n) = A255322(n) / (A272168(n) * A000178(n)).
a(n) ~ c1/c2 * A * exp(-1/12 + n/2 + n^2/4) * n^(1/12 + n^2/2) / (2*Pi)^(n/2), where c1 = Product_{k>=1} (k^2)!/stirling(k^2) = 1.14426047263759216966268786..., c2 = Product_{k>=2} (k*(k-1))!/stirling(k*(k-1)) = 1.086533635964823338078329..., stirling(n) = sqrt(2*Pi*n) * n^n / exp(n) is the Stirling approximation of n!, and A = A074962 is the Glaisher-Kinkelin constant.

A272095 a(n) = Product_{k=0..n} binomial(n^2,k).

Original entry on oeis.org

1, 1, 24, 27216, 1956864000, 11593630125000000, 7004354761049263478784000, 515246658615545697034849051407876096, 5368556637668593177532650186945239827409750982656, 9038577429104951379916309583338181472480254559457860096000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 20 2016

Keywords

Crossrefs

Cf. A272093, A272094, A272241.
Cf. A000178, A098694, A268196, A262261.

Programs

  • Mathematica
    Table[Product[Binomial[n^2, k], {k, 0, n}], {n, 0, 10}]
Table[((n^2)!)^(n+1) * BarnesG[n^2 - n + 1] / (BarnesG[n^2 + 2] * BarnesG[n+2]), {n, 0, 10}]

Formula

a(n) = ((n^2)!)^(n+1) / (A272164(n) * A000178(n)).
a(n) ~ A * exp(3*n^2/4 + 5*n/6 - 1/8) * n^(n^2/2 - 5/12) / (2*Pi)^((n+1)/2), where A = A074962 is the Glaisher-Kinkelin constant.

A272093 a(n) = Product_{k=0..n} binomial(k*n,k).

Original entry on oeis.org

1, 1, 12, 3780, 44844800, 26352845268750, 953083353075475894272, 2537540586421634737033298208000, 579150777545101402084349505293757972480000, 12933741941622730846344367593442776825612980847409218750, 31768605393074559234133528464091374346848946682424165820313600000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 20 2016

Keywords

Crossrefs

Cf. A272094, A272094, A272095.
Cf. A000178, A098694, A268196, A262261.

Programs

  • Mathematica
    Table[Product[Binomial[k*n, k], {k, 0, n}], {n, 0, 10}]

Formula

a(n) = A272096(n) / (A272166(n) * A000178(n)).
a(n) ~ A^2 * exp(n^2/2 + 3*n/4 + 1/12) * n^(n^2/2 - 1/3) / (2*Pi)^((n+1)/2), where A = A074962 is the Glaisher-Kinkelin constant.

A367568 a(n) = Product_{k=0..n} (4*k)! / k!^4.

Original entry on oeis.org

1, 24, 60480, 22353408000, 1409672968704000000, 16539333509029163728896000000, 38185078618454141182825889242546176000000, 18043150250179542387558306410182977707728856678400000000, 1796395750154420920494206475343190362781863323574704301041254400000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 23 2023

Keywords

Crossrefs

Cf. A000178, A008977, A268505, A168488, A268196, A262261.
Cf. A007685, A367567, A367569, A367570, A367571.

Programs

  • Mathematica
    Table[Product[(4*k)!/k!^4, {k, 0, n}], {n, 0, 10}]
Table[Product[Binomial[4*k,k] * Binomial[3*k,k] * Binomial[2*k,k], {k, 0, n}], {n, 0, 10}]

Formula

a(n) = Product_{k=0..n} binomial(4*k,k) * binomial(3*k,k) * binomial(2*k,k).
a(n) = A268505(n) / A000178(n)^4.
a(n) = A268505(n) / A168488(n).
a(n) = A007685(n) * A268196(n) * A262261(n).
a(n) ~ A^(15/4) * sqrt(Gamma(1/4)) * 2^(4*n^2 + 7*n/2 - 7/6) * exp(3*n/2 - 5/16) / (n^(3*n/2 + 17/16) * Pi^(3*n/2 + 7/4)), where A is the Glaisher-Kinkelin constant A074962.

A165975 a(n) = sqrt( binomial(4n,0) * binomial(4n,1) * ... * binomial(4n,2n-1) ).

Original entry on oeis.org

1, 2, 112, 261360, 27983155200, 143829595278720000, 36441048083860298170220544, 463109968103790656729135319264000000, 298869615482782118878970689211942578421760000000
Offset: 0

Views

Author

Max Alekseyev, Oct 02 2009

Keywords

Links

Crossrefs

Cf. A262261.

Programs

  • Mathematica
    Table[Sqrt[Product[Binomial[4*n, k], {k, 0, 2*n - 1}]], {n, 0, 5}] (* G. C. Greubel, Apr 19 2016 *)
  • PARI
    a(n) = sqrtint(prod(k=0, 2*n-1, binomial(4*n, k))); \\ Michel Marcus, Apr 19 2016

Formula

a(n) = (4n)!^n / A165970(n).
a(n) ~ A^(1/2) * exp(2*n^2 + n - 1/48) / (2^(5*n/2 + 1/6) * Pi^(n/2) * n^(n/2 - 1/24)), where A = A074962 is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Apr 19 2016
Showing 1-7 of 7 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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