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 1-4 of 4 results.

A129893 a(n) = s!/(s-n)! where s = (n*(n+1)/2)+1.

Original entry on oeis.org

1, 2, 12, 210, 7920, 524160, 53721360, 7866331200, 1556675366400, 399790821830400, 129210868410624000, 51295616536721356800, 24529502681864788608000, 13903600298770901182464000
Offset: 0

Views

Author

Kim Dong Seok (Go Jae Song, Nam Dae Young) from KNU (gjs0419(AT)nate.com), Jun 04 2007

Keywords

Comments

Bread Shop Open!. We have a loaf of bread which has a kernel of corns irregularly inside. We cut the loaf n times getting the maximal number (s, see A000124) of pieces and distribute one piece to each of n people. The remaining pieces of bread will be the prize for the winner. The sequence gives the number of cases when n pieces are distributed to n persons.

Examples

			a(2)=12 s=4,n=2 because we can write 12=4*3.
a(3)=210 s=7,n=3 because we can write 210=7*6*5.
		

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 72, Problem 2.
  • H. E. Dudeney, Amusements in Mathematics, Nelson, London, 1917, page 177.
  • N. Reading, On the structure of Bruhat Order, Ph.D. dissertation, University of Minnesota, anticipated 2002.
  • A. M. Robert, A Course in p-adic Analysis, Springer-Verlag, 2000; p. 213.
  • N. J. A. Sloane, On single-deletion-correcting codes, in Codes and Designs (Columbus, OH, 2000), 273-291, Ohio State Univ. Math. Res. Inst. Publ., 10, de Gruyter, Berlin, 2002.
  • W. A. Whitworth, DCC Exercises in Choice and Chance, Stechert, NY, 1945, p. 30.
  • A. M. Yaglom and I. M. Yaglom: Challenging Mathematical Problems with Elementary Solutions. Vol. I. Combinatorial Analysis and Probability Theory. New York: Dover Publications, Inc., 1987, p. 13, #44 (First published: San Francisco: Holden-Day, Inc., 1964)

Crossrefs

Programs

  • Haskell
    a129893 n = a129893_list !! n
    a129893_list = 1 : zipWith div (tail fs) fs where
       fs = map a000142 a000124_list
    -- Reinhard Zumkeller, Oct 03 2012
  • Mathematica
    Table[s=(n(n+1))/2+1;s!/(s-n)!,{n,0,20}] (* Harvey P. Dale, Nov 15 2012 *)
    #[[1]]!/(#[[1]]-#[[2]])!&/@With[{nn=20},Thread[{Accumulate[ Range[0,nn]]+ 1,Range[0,nn]}]] (* Harvey P. Dale, Sep 12 2015 *)

Formula

a(n) = sPn, where s=(n*(n+1)/2)+1.

Extensions

Typo fixed in a(13) by Reinhard Zumkeller, Oct 03 2012

A107869 Column 1 of triangle A107867; a(n) = binomial( n*(n+1)/2 + n+1, n).

Original entry on oeis.org

1, 3, 15, 120, 1365, 20349, 376740, 8347680, 215553195, 6358402050, 210980549208, 7778680504140, 315502265971620, 13961746143269400, 669413654240461560, 34569147570568156800, 1912924003884628655655, 112923282067713332728110
Offset: 0

Views

Author

Paul D. Hanna, Jun 04 2005

Keywords

Crossrefs

Programs

  • PARI
    a(n)=binomial(n*(n+1)/2+n+1,n)
    
  • Sage
    [binomial(binomial(binomial(n+1,n),n-1),n-1) for n in range(1, 19)] # Zerinvary Lajos, Nov 30 2009

A129933 a(n) = (n*(n+1)/2+1)!/n!.

Original entry on oeis.org

1, 2, 12, 840, 1663200, 174356582400, 1561112121913344000, 1754317855900734514790400000, 341362923889542287855059017400320000000, 15163751542692044063740921044974247390216192000000000, 195932150519417838363658963697014150610807423633478962380800000000000
Offset: 0

Views

Author

N. J. A. Sloane, Jun 06 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n (n+1)/2+1)!/n!,{n,0,20}] (* Harvey P. Dale, Aug 04 2022 *)

A176566 Triangle T(n, k) = binomial(n*(n+1)/2 + k, k), read by rows.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 4, 10, 20, 1, 7, 28, 84, 210, 1, 11, 66, 286, 1001, 3003, 1, 16, 136, 816, 3876, 15504, 54264, 1, 22, 253, 2024, 12650, 65780, 296010, 1184040, 1, 29, 435, 4495, 35960, 237336, 1344904, 6724520, 30260340, 1, 37, 703, 9139, 91390, 749398, 5245786, 32224114, 177232627, 886163135
Offset: 0

Views

Author

Roger L. Bagula, Apr 20 2010

Keywords

Examples

			Square array of T(n, k):
  1,  1,   1,    1,     1,     1,      1 ...
  1,  1,   1,    1,     1,     1,      1 ... A000012;
  1,  2,   3,    4,     5,     6,      7 ... A000027;
  1,  4,  10,   20,    35,    56,     84 ... A000292;
  1,  7,  28,   84,   210,   462,    924 ... A000579;
  1, 11,  66,  286,  1001,  3003,   8008 ... A001287;
  1, 16, 136,  816,  3876, 15504,  54264 ... A010968;
  1, 22, 253, 2024, 12650, 65780, 296010 ... A010974;
Triangle begins as:
  1;
  1,  1;
  1,  2,   3;
  1,  4,  10,   20;
  1,  7,  28,   84,   210;
  1, 11,  66,  286,  1001,   3003;
  1, 16, 136,  816,  3876,  15504,   54264;
  1, 22, 253, 2024, 12650,  65780,  296010,  1184040;
  1, 29, 435, 4495, 35960, 237336, 1344904,  6724520,  30260340;
  1, 37, 703, 9139, 91390, 749398, 5245786, 32224114, 177232627, 886163135;
		

Crossrefs

Cf. A107868 (rows sums), A158498.

Programs

  • Magma
    [Binomial(Binomial(n, 2) + k, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 09 2021
    
  • Mathematica
    T[n_, k_]= Binomial[Binomial[n, 2] + k, k];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten
  • PARI
    row(n) = vector(n+1, k, k--; binomial(binomial(n,2) + k, k)); \\ Michel Marcus, Jul 10 2021
  • Sage
    flatten([[binomial(binomial(n,2) +k, k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jul 09 2021
    

Formula

T(n, k) = binomial(binomial(n, 2) + k, k).
Sum_{k=0..n} T(n, k) = A107868(n).
Showing 1-4 of 4 results.