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

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

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Author

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).

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).

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

A014062 a(n) = binomial(n^2, n).

Original entry on oeis.org

1, 1, 6, 84, 1820, 53130, 1947792, 85900584, 4426165368, 260887834350, 17310309456440, 1276749965026536, 103619293824707388, 9176358300744339432, 880530516383349192480, 91005567811177478095440, 10078751602022313874633200, 1190739044344491048895397910
Offset: 0

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Author

Keywords

Comments

Roberts states that Gupta and Khare show that a(n) > A002110(n) for 2 < n < 1794 and that a(n) < A002110(n) for n >= 1794, where A002110(n) is the product of the first n primes. - T. D. Noe, Oct 03 2007
This sequence describes the number of ways to arrange n objects in an n X n array (for example, stars in a flag's field pattern). - Tom Young (mcgreg265(AT)msn.com), Jun 17 2010
It appears that a(n) == n (mod n^3) only if n is 1, an odd prime, the square of an odd prime, or the cube of an odd prime. - Gary Detlefs, Aug 06 2013; corrected by Michel Marcus, May 29 2015

References

  • J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 265.

Crossrefs

Main diagonal of A060539.

Programs

  • Magma
    [Binomial(n^2,n): n in [0..30]]; // G. C. Greubel, Apr 29 2024
    
  • Mathematica
    Table[Binomial[n^2,n],{n,0,22}] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2011 *)
    Table[SeriesCoefficient[(1+x)^(n^2), {x, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Aug 06 2025 *)
  • PARI
    {a(n) = sum(k=0, n, binomial(n, k)*binomial(n^2-n, k))}
    for(n=0,20,print1(a(n),", ")) \\ Paul D. Hanna, Nov 18 2015
    
  • SageMath
    [binomial(n^2,n) for n in range(31)] # G. C. Greubel, Apr 29 2024

Formula

a(n) ~ 1/sqrt(2*Pi) * (e*n)^(n - 1/2). - Charles R Greathouse IV, Jul 07 2007
a(n) = Sum_{k=0..n} binomial(n, k) * binomial(n^2 - n, k). - Paul D. Hanna, Nov 18 2015
a(n) = (n+1)*A177234(n). - R. J. Mathar, Jan 25 2019
From G. C. Greubel, Apr 29 2024: (Start)
a(n) = n*(n+1)*A177784(n).
a(n) = (n+1)*A177456(n)/(n-1).
a(n) = (n+1)*A177788(n)/n. (End)
a(n) = [x^n] (1+x)^(n^2). - Vaclav Kotesovec, Aug 06 2025

A004381 Binomial coefficient C(8n,n).

Original entry on oeis.org

1, 8, 120, 2024, 35960, 658008, 12271512, 231917400, 4426165368, 85113005120, 1646492110120, 32006008361808, 624668654531480, 12233149001721760, 240260199935164200, 4730523156632595024, 93343021201262177400, 1845382436487682488000
Offset: 0

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Author

Keywords

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.

Crossrefs

Row 8 of A060539.
binomial(k*n,n): A000984 (k = 2), A005809 (k = 3), A005810 (k = 4), A001449 (k = 5), A004355 (k = 6), A004368 (k = 7), A169958 - A169961 (k = 9 thru 12).

Programs

Formula

a(n) = C(8*n-1,n-1)*C(64*n^2,2)/(3*n*C(8*n+1,3)), n>0. - Gary Detlefs, Jan 02 2014
From Ilya Gutkovskiy, Jan 16 2017: (Start)
O.g.f.: 7F6(1/8,1/4,3/8,1/2,5/8,3/4,7/8; 1/7,2/7,3/7,4/7,5/7,6/7; 16777216*x/823543).
E.g.f.: 7F7(1/8,1/4,3/8,1/2,5/8,3/4,7/8; 1/7,2/7,3/7,4/7,5/7,6/7,1; 16777216*x/823543).
a(n) ~ 2^(24*n+1)/(sqrt(Pi*n)*7^(7*n+1/2)). (End)
From Peter Bala, Feb 20 2022: (Start)
The o.g.f. A(x) is algebraic: (1 - A(x))*(1 + 7*A(x))^7 + (8^8)*x*A(x)^8 = 0.
Sum_{n >= 1} a(n)*( x*(7*x + 8)^7/(8^8*(1 + x)^8) )^n = x. (End)
From Seiichi Manyama, Aug 16 2025: (Start)
a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(8*n+1,k).
G.f.: 1/(1 - 8*x*g^7) where g = 1+x*g^8 is the g.f. of A007556.
G.f.: g/(8-7*g) where g = 1+x*g^8 is the g.f. of A007556. (End)

A060543 Triangle, read by antidiagonals, where T(n,k) = C(n+n*k+k, n*k+k).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 10, 5, 1, 1, 35, 28, 7, 1, 1, 126, 165, 55, 9, 1, 1, 462, 1001, 455, 91, 11, 1, 1, 1716, 6188, 3876, 969, 136, 13, 1, 1, 6435, 38760, 33649, 10626, 1771, 190, 15, 1, 1, 24310, 245157, 296010, 118755, 23751, 2925, 253, 17, 1, 1, 92378, 1562275
Offset: 0

Views

Author

Henry Bottomley, Apr 02 2001

Keywords

Comments

Main diagonal is A108288. Antidiagonal sums is A108289. Inverse binomial transforms of each row give triangle A108290. G.f. of row n multiplied by (1-x)^(n+1) equals g.f. of row n of triangle A108267 (rows sums of A108267 equal (n+1)^n).

Examples

			row 1: (2*n+1)/1!
row 2: (3*n+1)*(3*n+2)/2!
row 3: (4*n+1)*(4*n+2)*(4*n+3)/3!
row 4: (5*n+1)*(5*n+2)*(5*n+3)*(5*n+4)/4!
row 5: (6*n+1)*(6*n+2)*(6*n+3)*(6*n+4)*(6*n+5)/5!.
Table begins:
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,...
1,3,5,7,9,11,13,15,17,19,21,23,25,27,...
1,10,28,55,91,136,190,253,325,406,496,...
1,35,165,455,969,1771,2925,4495,6545,...
1,126,1001,3876,10626,23751,46376,82251,...
1,462,6188,33649,118755,324632,749398,...
1,1716,38760,296010,1344904,4496388,...
		

Crossrefs

Cf. A108290, A108267, A108288, A108289, A060544 (row 2), A015219 (row 3).
Rows include A000012, A001700, A025174. Columns include A000012, A005408, A060544. Main diagonal is A060545.

Programs

  • PARI
    T(n,k)=binomial(n+n*k+k,n*k+k)
    
  • PARI
    { i=0; write("b060543.txt", "0 1"); for (m=0, 20, for (k=0, m + 1, n=m - k + 1; write("b060543.txt", i++, " ", binomial(n + n*k + k, n*k + k))); ) } \\ Harry J. Smith, Jul 06 2009

Formula

a(n) = A060539(n, k)/n = A007318(nk, k)/n = A060540(n, k)/A060540(n-1, k).

Extensions

Entry revised by Paul D. Hanna, May 31 2005
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 17 2007

A169961 a(n) = binomial(12*n, n).

Original entry on oeis.org

1, 12, 276, 7140, 194580, 5461512, 156238908, 4529365776, 132601016340, 3911395881900, 116068178638776, 3461014728350400, 103619293824707388, 3112781199432937200, 93780365051563029360, 2832430653037446854640, 85733828145510955528212, 2600022926684976508835280
Offset: 0

Views

Author

N. J. A. Sloane, Aug 07 2010

Keywords

Crossrefs

Programs

  • Magma
    [Binomial(12*n, n): n in [0..20]]; // Vincenzo Librandi, Aug 07 2014
    
  • Mathematica
    Table[Binomial[12 n, n], {n, 0, 20}] (* Vincenzo Librandi, Aug 07 2014 *)
    CoefficientList[Series[HypergeometricPFQ[Range[11]/12, Range[10]/11,(12^12)/(11^11)*x], {x,0,10}],x] (* Bradley Klee, Jul 01 2018 *)
  • PARI
    a(n) = binomial(12*n, n); \\ Michel Marcus, Jul 02 2018

Formula

a(n) = C(12*n-1,n-1)*C(144*n^2,2)/(3*n*C(12*n+1,3)), n>0. - Gary Detlefs, Jan 02 2014
From Bradley Klee, Jul 01 2018 : (Start)
G.f. G(x) and derivatives G^(n)(x)=d^n/dx^n G(x) satisfy a Picard-Fuchs type differential equation, 0=Sum_{m=0..11}(v1_{n}*x^(n+1)-v2_{n}*x^n)*G^(n)(x), with integer coefficient vectors:
v1={479001600, 647647046323200, 99278289544896000, 1290870365178240000, 4245175263164774400, 5313701967430348800, 3083267876011868160, 918801061774295040, 147161631039160320, 12624021804810240, 539424077119488, 8916100448256}
v2={0, 39916800, 14079254112000, 1273481816745600, 11475123393888000, 27687351298068000, 25909403608075680, 11200182937408080, 2427742942653600, 268452344620350, 14265583530550, 285311670611}
G.f.: G(x) = 11F10(m/12;n/11;12^12/11^11*x), m=1..11, n=1..10. (End)
From Vaclav Kotesovec, Jul 15 2018: (Start)
Recurrence: 11*n*(11*n - 10)*(11*n - 9)*(11*n - 8)*(11*n - 7)*(11*n - 6)*(11*n - 5)*(11*n - 4)*(11*n - 3)*(11*n - 2)*(11*n - 1)*a(n) = 41472*(2*n - 1)*(3*n - 2)*(3*n - 1)*(4*n - 3)*(4*n - 1)*(6*n - 5)*(6*n - 1)*(12*n - 11)*(12*n - 7)*(12*n - 5)*(12*n - 1)*a(n-1).
a(n) ~ 2^(24*n + 1/2) * 3^(12*n + 1/2) / (sqrt(Pi*n) * 11^(11*n + 1/2)). (End)
From Peter Bala, Feb 21 2022: (Start)
The o.g.f. A(x) is algebraic: (1 - A(x))*(1 + 11*A(x))^11 + (12^12)*x*A(x)^12 = 0.
Sum_{n >= 1} a(n)*( x*(11*x + 12)^11/(12^12*(1 + x)^12) )^n = x. (End)
From Seiichi Manyama, Aug 16 2025: (Start)
a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(12*n+1,k).
G.f.: 1/(1 - 12*x*g^11) where g = 1+x*g^12.
G.f.: g/(12-11*g) where g = 1+x*g^12. (End)

A060538 Square array read by antidiagonals of number of ways of dividing n*k labeled items into n labeled boxes with k items in each box.

Original entry on oeis.org

1, 1, 2, 1, 6, 6, 1, 20, 90, 24, 1, 70, 1680, 2520, 120, 1, 252, 34650, 369600, 113400, 720, 1, 924, 756756, 63063000, 168168000, 7484400, 5040, 1, 3432, 17153136, 11732745024, 305540235000, 137225088000, 681080400, 40320, 1, 12870
Offset: 1

Views

Author

Henry Bottomley, Apr 02 2001

Keywords

Examples

			       1        1        1        1
       2        6       20       70
       6       90     1680    34650
      24     2520   369600 63063000
		

Crossrefs

Subtable of A187783.
Rows include A000012, A000984, A006480, A008977, A008978 etc.
Columns include A000142, A000680, A014606, A014608, A014609 etc.
Main diagonal is A034841.

Programs

  • PARI
    T(n,k)=(n*k)!/k!^n;
    for(n=1, 6, for(k=1, 6, print1(T(n,k), ", ")); print) \\ Harry J. Smith, Jul 06 2009

Formula

T(n, k) = (nk)!/k!^n = T(n-1, k)*binomial(nk, k) = T(n-1, k)*A060539(n, k) = A060540(n, k)*A000142(k).

A060541 a(n) = binomial(4*n, 4).

Original entry on oeis.org

1, 70, 495, 1820, 4845, 10626, 20475, 35960, 58905, 91390, 135751, 194580, 270725, 367290, 487635, 635376, 814385, 1028790, 1282975, 1581580, 1929501, 2331890, 2794155, 3321960, 3921225, 4598126, 5359095, 6210820, 7160245, 8214570, 9381251, 10668000, 12082785
Offset: 1

Views

Author

Henry Bottomley, Apr 02 2001

Keywords

Crossrefs

Programs

  • Magma
    [Binomial(4 n, 4): n in [1..40]]; // Vincenzo Librandi, Jan 20 2015
  • Mathematica
    Table[Binomial[4n, 4], {n, 100}] (* Wesley Ivan Hurt, Sep 27 2013 *)
    LinearRecurrence[{5,-10,10,-5,1},{1,70,495,1820,4845},40] (* Harvey P. Dale, Jan 13 2015 *)
  • PARI
    a(n) = n*(2*n - 1)*(4*n - 1)*(4*n - 3)/3; \\ Harry J. Smith, Jul 06 2009
    

Formula

a(n) = n*(2n-1)*(4n-1)*(4n-3)/3.
a(n) = n * A015219(n-1) = A000332(4n) = A060539(n, 4).
G.f.: x*(1+65*x+155*x^2+35*x^3) / (1-x)^5. - R. J. Mathar, Oct 03 2011
From Amiram Eldar, Mar 08 2022: (Start)
Sum_{n>=1} 1/a(n) = 6*log(2) - Pi.
Sum_{n>=1} (-1)^(n+1)/a(n) = 2*sqrt(2)*log(sqrt(2)-1) - log(2) + (2*sqrt(2) - 3/2)*Pi. (End)

Extensions

Offset changed from 0 to 1 by Harry J. Smith, Jul 06 2009

A295772 a(n) = Sum_{k=0..n} binomial((n-k)*k, k).

Original entry on oeis.org

1, 1, 2, 4, 11, 41, 189, 1020, 6277, 43262, 328963, 2727076, 24425913, 234743744, 2406904525, 26202132494, 301579542517, 3656552470482, 46555182556971, 620695577790512, 8644238847922949, 125472134647552497, 1894393648378487895, 29696659293381522674
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 27 2017

Keywords

Examples

			G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 11*x^4 + 41*x^5 + 189*x^6 + 1020*x^7 + 6277*x^8 + 43262*x^9 + 328963*x^10 + ...
		

Crossrefs

Programs

  • Maple
    seq(add(binomial((n-k)*k,k),k=0..n),n=0..30); # Robert Israel, Nov 27 2017
  • Mathematica
    Table[Sum[Binomial[(n-k)*k, k], {k, 0, n}], {n, 0, 30}]

Formula

log(a(n)) ~ n*(log(n) - log(log(n)) + (log(log(n)) - 1)/log(n)). - Vaclav Kotesovec, Jan 10 2023
G.f. A(x) = 1 + x*Sum_{n>=0} x^n/n! * ( d^n/dy^n (1+y)^n/(1 - x*(1+y)^n) ) evaluated at y = 0. - Paul D. Hanna, Nov 13 2024

A323663 Square array A(n,k), n >= 1, k >= 1, read by antidiagonals, where A(n,k) is Sum_{j=1..n} binomial(j*k, k).

Original entry on oeis.org

1, 1, 3, 1, 7, 6, 1, 21, 22, 10, 1, 71, 105, 50, 15, 1, 253, 566, 325, 95, 21, 1, 925, 3256, 2386, 780, 161, 28, 1, 3433, 19489, 18760, 7231, 1596, 252, 36, 1, 12871, 119713, 154085, 71890, 17857, 2926, 372, 45, 1, 48621, 748342, 1303753, 747860, 214396, 38332, 4950, 525, 55
Offset: 1

Views

Author

Seiichi Manyama, Jan 23 2019

Keywords

Examples

			Square array begins:
    1,   1,    1,     1,       1,        1, ...
    3,   7,   21,    71,     253,      925, ...
    6,  22,  105,   566,    3256,    19489, ...
   10,  50,  325,  2386,   18760,   154085, ...
   15,  95,  780,  7231,   71890,   747860, ...
   21, 161, 1596, 17857,  214396,  2695652, ...
   28, 252, 2926, 38332,  539028,  7941438, ...
   36, 372, 4950, 74292, 1197036, 20212950, ...
		

Crossrefs

Columns 1-3 give A000217, A002412, A116689.
Rows 1-3 give A000012, A244174, A029848.
Main diagonal is A096131.
Cf. A060539.

A066704 Triangle with a(n,k) = C(n,floor(n/k)) with n>=k>=1.

Original entry on oeis.org

1, 1, 2, 1, 3, 3, 1, 6, 4, 4, 1, 10, 5, 5, 5, 1, 20, 15, 6, 6, 6, 1, 35, 21, 7, 7, 7, 7, 1, 70, 28, 28, 8, 8, 8, 8, 1, 126, 84, 36, 9, 9, 9, 9, 9, 1, 252, 120, 45, 45, 10, 10, 10, 10, 10, 1, 462, 165, 55, 55, 11, 11, 11, 11, 11, 11, 1, 924, 495, 220, 66, 66, 12, 12, 12, 12, 12, 12
Offset: 1

Views

Author

Henry Bottomley, Jan 14 2002

Keywords

Examples

			Rows start:
  1;
  1,  2;
  1,  3, 3;
  1,  6, 4, 4;
  1, 10, 5, 5, 5;
  ...
		

Crossrefs

Row sums are A051054.
Columns include (most of) A000012, A001405, A051033, A051036, A051052, A051053, A062947 etc.
n appears A008619 times in the n-th row.
Cf. A060539.
Showing 1-10 of 13 results. Next