A174560
Number of 3 X n Latin rectangles whose second row has cycles of even length only.
Original entry on oeis.org
0, 24, 0, 18000, 0, 52254720
Offset: 3
A174581
Let J_n be an n X n all-1's matrix, I = I_n the n X n identity matrix and P = P_n the incidence matrix of the cycle (1,2,3,...,n). Then a(n) is the number of (0,1) n X n matrices A <= J_n - I - P - P^2 with exactly two 1's in every row and column.
Original entry on oeis.org
0, 1, 20, 1266, 102574, 9746472
Offset: 4
- V. S. Shevelev, Development of the rook technique for calculating the cyclic indicators of (0,1)-matrices, Izvestia Vuzov of the North-Caucasus region, Nature sciences 4 (1996), 21-28 (in Russian).
- S. E. Grigorchuk, V. S. Shevelev, An algorithm of computing the cyclic indicator of couples discordant permutations with restricted position, Izvestia Vuzov of the North-Caucasus region, Nature sciences 3 (1997), 5-13 (in Russian).
A001627
Related to Latin rectangles.
Original entry on oeis.org
1, 0, 2, 44, 1008, 34432, 1629280, 101401344, 8030787968, 788377273856, 93933191303424, 13350759115563520, 2231133728986759168, 433075048506207645696, 96617322164029448916992, 24549315871469898190266368, 7047652261245574026565877760
Offset: 1
- 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, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
A170904
Sequence obtained by a formal reading of Riordan's Eq. (30a), p. 206.
Original entry on oeis.org
1, 0, 0, 2, 24, 572, 21280, 1074390, 70299264, 5792903144, 587159944704, 71822748886440, 10435273503677440, 1776780701352504408, 350461958856515690496, 79284041282799128098778, 20392765404792755583221760, 5917934230798152486136427600, 1924427226324694427836833857536
Offset: 0
- J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, pp. 206, 209.
-
# A000166
unprotect(D);
D := proc(n) option remember; if n<=1 then 1-n else (n-1)*(D(n-1)+D(n-2)); fi; end;
[seq(D(n),n=0..30)];
# A335700 (equals A000179 except that A335700(1) = 0)
U := proc(n) if n<=1 then 1-n else add ((-1)^k*(2*n)*binomial(2*n-k, k)*(n-k)!/(2*n-k), k=0..n); fi; end;
[seq(U(n),n=0..30)];
# bad A000186 (A170904)
Kbad:=proc(n) local k; global D, U; add( binomial(n,k)*D(n-k)*D(k)*U(n-2*k), k=0..floor(n/2) ); end;
[seq(Kbad(n),n=0..30)];
A174561
Number of 3 X n Latin rectangles whose second row contains two cycles with the same order of its elements, e.g., the cycle (x_2, x_3, ..., x_k, x_1) with x_1 < x_2 < ... < x_k.
Original entry on oeis.org
12, 120, 2020, 32410, 563948
Offset: 4
A174582
Let J_n be n X n matrix which contains 1's only, I=I_n be the n X n identity matrix and P=P_n be the incidence matrix of the cycle (1,2,3,...,n). Then a(n) is the number of (0,1,2) n X n matrices A<=2(J_n-I-P-P^2) with exactly one 1 and one 2 in every row and column.
Original entry on oeis.org
0, 2, 72, 3722, 329192, 32842446
Offset: 4
- V. S. Shevelev, Development of the rook technique for calculating the cyclic indicators of (0,1)-matrices, Izvestia Vuzov of the North-Caucasus region, Nature sciences 4 (1996), 21-28 (in Russian).
- S. E. Grigorchuk, V. S. Shevelev, An algorithm of computing the cyclic indicator of couples discordant permutations with restricted position, Izvestia Vuzov of the North-Caucasus region, Nature sciences 3 (1997), 5-13 (in Russian).
A275921
Number of 5 X n Latin rectangles.
Original entry on oeis.org
56, 9408, 11270400, 27206658048, 112681643083776, 746988383076286464, 7533492323047902093312, 111048869433803210653040640, 2315236533572491933131807916032, 66415035616070432053233927044726784, 2560483881619577552584872021599994249216
Offset: 5
A001568
Related to 3-line Latin rectangles.
Original entry on oeis.org
1, -1, -1, 2, 49, 629, 6961, 38366, -1899687, -133065253, -6482111309, -281940658286, -10702380933551, -247708227641863, 14512103549430397, 3377044611825908414, 433180638973276282801, 47474992085447610990231
Offset: 1
- S. M. Kerawala, The asymptotic number of three-deep Latin rectangles, Bull. Calcutta Math. Soc., 39 (1947), 71-72.
- N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
-
def A001568(N):
a = polygen(QQ, 'a')
R = PowerSeriesRing(a.parent(), 't', default_prec=N + 2)
t = R.gen()
n = 1 / t
dico = {0: 1}
for k in range(1, N + 1):
U = sum(di * t**i / factorial(i) for i, di in dico.items())
U += a * t**k / factorial(k)
U = U.O(k + 2)
delta = -U+(n-1)*(n**2-2*n+2)/n**2/(n-2)*U(t=1/(n-1))+(n**2-2*n+2)/n**2/(n-1)*U(t=1/(n-2))+(n**2-2*n-2)/n**2/(n-1)/(n-2)**2*U(t=1/(n-3))+2*(n*n-5*n+3)/n**2/(n-1)/(n-2)**2/(n-3)*U(t=1/(n-4))-4/n**2/(n-2)**2/(n-3)/(n-4)*U(t=1/(n-5))
dico[k] = delta[k + 1].numerator().roots()[0][0]
return list(dico.values())
# F. Chapoton, Jan 01 2022
A098276
Difference between the number of even reduced Latin rectangles of size 3 X n and the number of odd ones.
Original entry on oeis.org
1, 0, 2, 0, 72, -320, 3600, -32256, 344960, -3926016, 48625920, -648243200, 9270125568, -141579509760, 2300668418048, -39642283376640, 722055883161600, -13863472939925504, 279868860012625920
Offset: 1
-
Rest[CoefficientList[Series[x + ((1-x)^2/(1+x)+x/(1+x)^2)*E^(2*x), {x, 0, 20}], x]* Range[0, 20]!] (* Vaclav Kotesovec, Sep 29 2013 *)
-
a(n)=polcoeff(serlaplace(exp(2*x)*((1-x)^2/(1+x)+x/(1+x)^2)),n)
-
a(n)=(-1)^(n-1)*(n-2)*n!/2*polcoeff(Ser(exp(2*(atanh(x)-x))),n)
A174563
Number of 3 X n Latin rectangles such that every element of the second row has the same cyclic order (see comment).
Original entry on oeis.org
1, 14, 133, 3300, 93889, 3391086, 148674191, 7796637196, 480640583751, 34370030511334, 2818294139246649, 262403744798653716, 27506121212584723373, 3222018028986227724702, 418998630100386520363619, 60138044879434564251209580, 9477043948863636836099726259, 1632099068624734991723488992214
Offset: 3
- V. S. Shevelev, Reduced Latin rectangles and square matrices with equal row and column sums, Diskr. Mat. [Journal published by the Academy of Sciences of Russia], 4 (1992), 91-110.
- V. S. Shevelev, Modern enumeration theory of permutations with restricted positions, Diskr. Mat., 1993, 5, no.1, 3-35 (Russian) [English translation in Discrete Math. and Appl., 1993, 3:3, 229-263 (pp. 255-257)].
Comments