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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A001009 Triangle giving number L(n,k) of normalized k X n Latin rectangles.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 3, 4, 4, 1, 11, 46, 56, 56, 1, 53, 1064, 6552, 9408, 9408, 1, 309, 35792, 1293216, 11270400, 16942080, 16942080, 1, 2119, 1673792, 420909504, 27206658048, 335390189568, 535281401856, 535281401856, 1, 16687, 103443808
Offset: 1

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Keywords

References

  • CRC Handbook of Combinatorial Designs, 1996, p. 104.

Crossrefs

Rows include A001623, A000573. Diagonals include A000576.

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 12 2010

A003170 Number of 4 X n Latin rectangles in which the first row is in order.

Original entry on oeis.org

24, 1344, 393120, 155185920, 88390995840, 69761852246016, 74175958614030336, 103657593656495554560, 186355188348102566876160, 423073240119513285788344320, 1193404222275011001999025311744, 4123706289611916312851104783171584, 17237448791456599571078045378751528960
Offset: 4

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Author

Keywords

References

  • S. M. Kerawala, The enumeration of the Latin rectangle of depth three by means of a difference equation, Bull. Calcutta Math. Soc., 33 (1941), 119-127.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Equals A000573*(n-1)!/(n-4)!.

Programs

  • GAP
    ChooseList:=function(a,B) local x,p,i; x:=a; p:=1; for i in B do p:=p*Binomial(x,i); x:=x-i; od; return p; end;;
    DoylePartitions:=function(n) return Union(List(Partitions(n+8,8)-1,P->PermutationsList(P))); end;;
    DoyleF1:=function(A) return A[1]+A[3]+A[2]+A[4]; end;;
    DoyleF2:=function(A) return A[1]+A[2]+A[5]+A[6]; end;;
    DoyleF3:=function(A) return A[1]+A[3]+A[5]+A[7]; end;;
    DoyleF12:=function(A) return A[1]+A[2]; end;;
    DoyleF23:=function(A) return A[1]+A[5]; end;;
    DoyleF13:=function(A) return A[1]+A[3]; end;;
    DoyleF123:=function(A) return A[1]; end;;
    DoyleG:=function(A) return DoyleF1(A)*DoyleF2(A)*DoyleF3(A) -DoyleF12(A)*DoyleF3(A) -DoyleF23(A)*DoyleF1(A) -DoyleF13(A)*DoyleF2(A) +2*DoyleF123(A); end;;
    DoyleGProduct:=function(A) local i,p,B; p:=1; for i in [1..8] do B:=List(A,j->j); B[i]:=B[i]-1; B[8]:=B[8]+1; p:=p*DoyleG(B)^A[i]; od; return p; end;;
    NrFourLineNormalisedLatinRectanglesDoyle:=function(n) local count,A; count:=0; for A in DoylePartitions(n) do count:=count+(-1)^(A[2]+A[3]+A[5]+2*(A[4]+A[6]+A[7])+3*A[8])*ChooseList(n,A)*DoyleGProduct(A); od; return count; end;; # Douglas Stones (douglas.stones(AT)sci.monash.edu.au), Apr 01 2009, Sep 05 2009

Extensions

Doron Zeilberger pointed out that was an error in a(10), which has now been corrected.
More terms from Douglas Stones (douglas.stones(AT)sci.monash.edu.au), Apr 01 2009
Showing 1-2 of 2 results.