OFFSET
4,1
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).
LINKS
Douglas Stones, Table of n, K(4,n) for n=4..80
F. W. Light, Jr., A procedure for the enumeration of 4 X n Latin rectangles, Fib. Quart., 11 (1973), 241-246.
B. D. McKay and E. Rogoyski, Latin squares of order ten, Electron. J. Combinatorics, 2 (1995) #N3.
Douglas Stones, Doyle's formula for the number of reduced 6xn Latin rectangles
Douglas Stones, Enumeration Of Latin Squares And Rectangles
D. S. Stones, The many formulas for the number of Latin rectangles, Electron. J. Combin 17 (2010), A1.
D. S. Stones and I. M. Wanless, Divisors of the number of Latin rectangles, J. Combin. Theory Ser. A 117 (2010), 204-215.
PROG
(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
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
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
STATUS
approved