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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A210590 Triangle of numbers generated by the Nekrasov-Okounkov formula.

Original entry on oeis.org

1, 1, 1, 4, 5, 1, 18, 29, 12, 1, 120, 218, 119, 22, 1, 840, 1814, 1285, 345, 35, 1, 7920, 18144, 14674, 5205, 805, 51, 1, 75600, 196356, 185080, 79219, 16450, 1624, 70, 1, 887040, 2427312, 2515036, 1258628, 324569, 43568, 2954, 92, 1, 10886400, 32304240, 37012572, 21034376, 6431733, 1088409, 101178, 4974, 117, 1
Offset: 0

Views

Author

Wouter Meeussen, Mar 24 2012

Keywords

Comments

Row sums are A000712, alternating sign row sums are zero (except for first row); application of the Nekrasov-Okounkov formula; see A138782.

Examples

			Table starts as:
     1;
     1,     1;
     4,     5,     1;
    18,    29,    12,    1;
   120,   218,   119,   22,   1;
   840,  1814,  1285,  345,  35,  1;
  7920, 18144, 14674, 5205, 805, 51,  1;
  ...
		

Crossrefs

T(2n,n) gives A338755.

Programs

  • Mathematica
    w=9; MapIndexed[ CoefficientList[#1,t] Tr[#2-1]! &, CoefficientList[Series[Product[(1-x^i)^(-1-t), {i,w}], {x,0,w}], x]];
    or alternatively:
    CoefficientList[#, t] & /@ Table[1/n! Tr[(NumberOfTableaux[#1]^2 Apply[Times, t + Flatten[hooklength[#1]]^2] &) /@ Partitions[n]], {n,0,9}]
    or alternatively:
    Table[1/n!Tr[NumberOfTableaux[#]^2 f[ Flatten[hooklength[#]]^2,e,k,n ]&/@ Partitions[n] ],{n,0,9},{k,0,n}]
    with e and f defined as:
    e[n_,v_]:= Tr[Times @@@ Select[Subsets[Table[Subscript[x,j],{j,v}]],Length[#]==n&]];
    f[li_List,fun_,par_,k_]:=fun[par,k]/.Thread[Array[Subscript[x,#1]&,Length[li]]->li];

Formula

E.g.f.: Product_{i=1..n} (1 - x^i)^(-1 - t).

A138784 a(n) = n*(n-1)*(n-2)(27*n^3 - 174*n^2 + 511*n - 552)*n!/48.

Original entry on oeis.org

0, 0, 108, 5232, 154200, 3747600, 82908000, 1756661760, 36715472640, 770648256000, 16426162368000, 358029745920000, 8015066233574400, 184788598259865600, 4394609711331840000, 107899664364011520000
Offset: 1

Views

Author

Emeric Deutsch, May 15 2008

Keywords

Comments

a(n) = Sum [f(L)^2 Sum h(u)^2*h(v)^2h(w)^2], where L is a partition of n, f(L) is the number of standard Young tableaux of shape L, h(z) is the hook length of the box z in L (i.e., in the Ferrers diagram of L), the inner summation is over all unordered triples of distinct boxes u, v and w in L and the outer summation is over all partitions of n. Example: a(3)=108 because for the partitions L=(3), (2,1), (1,1,1) of n=3 the values of f(L) are 1, 2, 1, respectively, the hook length multi-sets are {3,2,1}, {3,1,1},{3,2,1}, respectively, Sum h(u)^2*h(v)^2*h(w)^2 = 36, 9, 36, respectively and now a(n) 1^2*36 + 2^2*9 + 1^2*36 = 108.
In Proposition 6.12 of the Han paper the number 600 should be replaced by 552. - Emeric Deutsch, Dec 07 2015

Crossrefs

Programs

  • Magma
    [n*(n-1)*(n-2)*(27*n^3-174*n^2+511*n-552)*Factorial(n)/48: n in [1..25]]; // Vincenzo Librandi, Dec 08 2015
  • Maple
    A138784 := proc(n)
        n*(n-1)*(n-2)*(27*n^3-174*n^2+511*n-552)*factorial(n)/48 ;
    end proc:
    seq(A138784(n),n=1..30) ;
  • Mathematica
    Table[n (n - 1) (n - 2) (27 n^3 - 174 n^2 + 511 n - 552) n!/48, {n, 25}] (* Vincenzo Librandi, Dec 08 2015 *)
  • PARI
    a(n) = n*(n-1)*(n-2)*(27*n^3-174*n^2+511*n-552)*n!/48; \\ Altug Alkan, Dec 07 2015
    

Formula

D-finite 9*(n-3) *(4179399*n -20778487) *a(n) +(-37614591*n^3 -15080676*n^2 +317158871*n +3150537632) *a(n-1) +2*(44621643*n +200235296) *(-1+n)^2*a(n-2)=0. - R. J. Mathar, Dec 10 2015
Showing 1-2 of 2 results.