A008305
Triangle read by rows: a(n,k) = number of permutations of [n] allowing i->i+j (mod n), j=0..k-1.
Original entry on oeis.org
1, 1, 2, 1, 2, 6, 1, 2, 9, 24, 1, 2, 13, 44, 120, 1, 2, 20, 80, 265, 720, 1, 2, 31, 144, 579, 1854, 5040, 1, 2, 49, 264, 1265, 4738, 14833, 40320, 1, 2, 78, 484, 2783, 12072, 43387, 133496, 362880, 1, 2, 125, 888, 6208, 30818, 126565, 439792, 1334961, 3628800
Offset: 1
a(4,3) = 9 because 9 permutations of {1,2,3,4} are allowed if each i can be placed on 3 positions i+0, i+1, i+2 (mod 4): 1234, 1423, 1432, 3124, 3214, 3412, 4123, 4132, 4213.
Triangle begins:
1,
1, 2,
1, 2, 6,
1, 2, 9, 24,
1, 2, 13, 44, 120,
1, 2, 20, 80, 265, 720,
1, 2, 31, 144, 579, 1854, 5040,
1, 2, 49, 264, 1265, 4738, 14833, 40320,
1, 2, 78, 484, 2783, 12072, 43387, 133496, 362880,
1, 2, 125, 888, 6208, 30818, 126565, 439792, 1334961, 3628800,
...
- H. Minc, Permanents, Encyc. Math. #6, 1978, p. 48
- Alois P. Heinz, Rows n = 1..23, flattened
- Henry Beker and Chris Mitchell, Permutations with restricted displacement, SIAM J. Algebraic Discrete Methods 8 (1987), no. 3, 338--363. MR0897734 (89f:05009)
- N. S. Mendelsohn, Permutations with confined displacement, Canad. Math. Bull., 4 (1961), 29-38.
- N. Metropolis, M. L. Stein, P. R. Stein, Permanents of cyclic (0,1) matrices, J. Combin. Theory, 7 (1969), 291-321.
- Wikipedia, Permanent (mathematics)
-
with(LinearAlgebra):
a:= (n, k)-> Permanent(Matrix(n,
(i, j)-> `if`(0<=j-i and j-i
-
a[n_, k_] := Permanent[Table[If[0 <= j-i && j-i < k || j-i < k-n, 1, 0], {i, 1,n}, {j, 1, n}]]; Table[Table[a[n, k], {k, 1, n}], {n, 1, 10}] // Flatten (* Jean-François Alcover, Mar 10 2014, after Alois P. Heinz *)
A184965
Number of permutations p of [n] such that (n-p(i)+i) mod n >= 6 for all i.
Original entry on oeis.org
1, 0, 0, 0, 0, 0, 0, 1, 2, 78, 888, 13909, 204448, 3182225, 51504968, 873224962, 15498424578, 287972983669, 5598118158336, 113756109812283, 2413723031593090, 53416658591208438, 1231458960862452472, 29538634475147637783, 736321207493996695072
Offset: 0
a(8) = 2: (2,3,4,5,6,7,8,1), (3,4,5,6,7,8,1,2).
-
with(LinearAlgebra):
a:= n-> `if`(n=0, 1, Permanent(Matrix(n, (i, j)->
`if`(i-j<=0 and i-j>-6 or i-j>n-6, 0, 1)))):
seq(a(n), n=0..15);
-
a[n_] := Permanent[Table[If[i-j <= 0 && i-j > -6 || i-j > n-6, 0, 1], {i, 1, n}, {j, 1, n}]]; a[0] = 1; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 15}] (* Jean-François Alcover, Jan 07 2016, adapted from Maple *)
A189389
Number of permutations p of [n] such that (n-p(i)+i) mod n >= 5 for all i.
Original entry on oeis.org
1, 0, 0, 0, 0, 0, 1, 2, 49, 484, 6208, 79118, 1081313, 15610304, 238518181, 3850864416, 65598500129, 1177003136892, 22203823852849, 439598257630414, 9117748844458320, 197776095898147080, 4479171132922158213, 105749311074795459594, 2598770324359627927649
Offset: 0
a(7) = 2: (2,3,4,5,6,7,1), (3,4,5,6,7,1,2).
-
with(LinearAlgebra):
a:= n-> `if`(n=0, 1, Permanent(Matrix(n, (i, j)->
`if`(i-j<=0 and i-j>-5 or i-j>n-5, 0, 1)))):
seq(a(n), n=0..15);
-
a[n_] := Permanent[Table[If[i-j <= 0 && i-j > -5 || i-j > n-5, 0, 1], {i, 1, n}, {j, 1, n}]]; a[0] = 1; Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Jan 07 2016, adapted from Maple *)
A061702
Triangle T(n,k) defined by Sum_{n >= 0,m >= 0} T(n,m)*x^m*y^n = 1 + y*(1 + 3*x - 4*x^2*y - 3*x^2*y^2 - 3*x^3*y^2 + 4*x^4*y^3)/((1 - y - 2*x*y - x*y^2 + x^3*y^3)*(1 - x*y)).
Original entry on oeis.org
1, 1, 3, 1, 6, 5, 1, 9, 18, 6, 1, 12, 42, 44, 9, 1, 15, 75, 145, 95, 13, 1, 18, 117, 336, 420, 192, 20, 1, 21, 168, 644, 1225, 1085, 371, 31, 1, 24, 228, 1096, 2834, 3880, 2588, 696, 49, 1, 27, 297, 1719, 5652, 10656, 11097, 5823, 1278, 78, 1, 30, 375, 2540, 10165
Offset: 0
Triangle begins:
1,
1,3,
1,6,5,
1,9,18,6,
1,12,42,44,9,
1,15,75,145,95,13,
1,18,117,336,420,192,20,
1,21,168,644,1225,1085,371,31,
1,24,228,1096,2834,3880,2588,696,49,
1,27,297,1719,5652,10656,11097,5823,1278,78,
1,30,375,2540,10165,24626,35045,29380,12535,2310,125,
... (from _N. J. A. Sloane_, Jun 28 2015)
Sum_{n, k} T(n, k) u^n t^k = 1 + (1 + 3*t)*u + (1 + 6*t + 5*t^2)*u^2 + ...
- R. P. Stanley, Enumerative Combinatorics I, Example 4.7.17.
-
max = 11; f[x_, y_] := 1 + y*(1 + 3*x - 4*x^2*y - 3*x^2*y^2 - 3*x^3*y^2 + 4*x^4*y^3)/((1 - y - 2*x*y - x*y^2 + x^3*y^3)*(1 - x*y)); se = Series[f[x, y], {x, 0, max}, {y, 0, max}]; coes = CoefficientList[se, {x, y}] ; t[n_, k_] := coes[[k, n]]; Flatten[ Table[t[n, k], {n, 1, max}, {k, 1, n}]](* Jean-François Alcover, Oct 24 2011 *)
A321352
Triangle T(n,k) giving the number of permutations pi of {1,2,...,n} such that for all i, pi(i) is not in {i, i+1, ..., i+k-1} (mod n), with 0 <= k <= n - 1.
Original entry on oeis.org
1, 2, 1, 6, 2, 1, 24, 9, 2, 1, 120, 44, 13, 2, 1, 720, 265, 80, 20, 2, 1, 5040, 1854, 579, 144, 31, 2, 1, 40320, 14833, 4738, 1265, 264, 49, 2, 1, 362880, 133496, 43387, 12072, 2783, 484, 78, 2, 1, 3628800, 1334961, 439792, 126565, 30818, 6208, 888, 125, 2, 1
Offset: 1
Table begins:
1
2, 1
6, 2, 1
24, 9, 2, 1
120, 44, 13, 2, 1
720, 265, 80, 20, 2, 1
5040, 1854, 579, 144, 31, 2, 1
40320, 14833, 4738, 1265, 264, 49, 2, 1
362880, 133496, 43387, 12072, 2783, 484, 78, 2, 1
A324622
Number of permutations p of [2+n] such that n is the maximum of the number of elements in any integer interval [p(i)..i+(2+n)*[i
Original entry on oeis.org
0, 1, 1, 11, 60, 435, 3473, 31315, 313227, 3445641, 41341502, 537313583, 7520316423, 112771887719, 1803821926465, 30656189582521, 551659191788556, 10478765887885181, 209522984620760153, 4398943767896801309, 96755196700729056267, 2224901906327124750355
Offset: 0
A324623
Number of permutations p of [3+n] such that n is the maximum of the number of elements in any integer interval [p(i)..i+(3+n)*[i
Original entry on oeis.org
0, 1, 1, 18, 113, 1001, 9289, 95747, 1075779, 13129188, 173006731, 2449243815, 37082963875, 598045522873, 10236223969309, 185344819109346, 3539853769700281, 71122126197951465, 1499666213536206971, 33113352117542113491, 764116379880803291501
Offset: 0
A061703
G.f.: 2*x*(2-2*x-3*x^2+2*x^3)/((1-3*x-x^2+x^3)*(1-x)).
Original entry on oeis.org
0, 4, 12, 34, 108, 344, 1104, 3546, 11396, 36628, 117732, 378426, 1216380, 3909832, 12567448, 40395794, 129844996, 417363332, 1341539196, 4312135922, 13860583628, 44552347608, 143205490528, 460308235562, 1479577849604
Offset: 0
- R. P. Stanley, Enumerative Combinatorics I, Example 4.7.17.
A264801
Number of essentially different seating arrangements for 2n couples around a circular table with 4n seats such that no spouses are neighbors, the neighbors of each person have opposite gender and no person's neighbors belong to the same couple.
Original entry on oeis.org
0, 6, 2400, 6375600, 45927907200, 713518388352000, 21216194909362252800, 1105729617210350356224000, 94398452626533646953922560000, 12514511465855205467497303154688000, 2467490887755897725667792936979169280000, 698323914872709997998407130752506728284160000
Offset: 1
a(1)=0 because with 2 couples it is impossible to satisfy all three conditions.
a(2)=6 because only the following arrangements are possible with 4 couples: ABdaCDbc, ABcaDCbd, ACdaBDcb, ACbaDBcd, ADcaBCdb, ADbaCBdc. This corresponds to the (2*2-1)! possibilities for persons B, C and D to choose a seat. After the positions of A, B, C and D are fixed, only A000183(2*2)=1 possibility remains to arrange their spouses a, b, c and d.
-
a000183(N)={my(a0=[0,0,0,1,2,20],a=vector(N),
f(x)=fibonacci(x-1)+fibonacci(x+1)+2;);
if(N<7,a=a0[1..N],for(k=1,6,a[k]=a0[k]);
for(n=7,N,a[n] = (-1)^n*(4*n+f(n)) +
(n/(n-1))*((n+1)*a[n-1] + 2*(-1)^n*f(n-1))
- ((2*n)/(n-2))*((n-3)*a[n-2] + (-1)^n*f(n-2))
+ (n/(n-3))*((n-5)*a[n-3] + 2*(-1)^(n-1)*f(n-3))
+ (n/(n-4))*(a[n-4] + (-1)^(n-1)*f(n-4))));a};
a264901(limit)={my(a183=a000183(2*limit)); for(n=1,limit,print1((2*n-1)!*a183[2*n],", "))};
a264901(12) \\ Hugo Pfoertner, Sep 05 2020
A002633
Related to discordant permutations.
Original entry on oeis.org
1, -3, 5, -3, 9, -3, -51, -675, -5871, -46467, -331371, -1852227, -920295, 224455293, 5571057501, 104877816093, 1781775072801, 28519837563645, 431525731169061, 5994769814117757, 68879336771960361, 346333945918252797, -15047168730918615315, -793523760950138583843
Offset: 0
- 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).
- K. Yamamoto, Structure polynomial of Latin rectangles and its application to a combinatorial problem, Memoirs of the Faculty of Science, Kyusyu University, Series A, 10 (1956), 1-13.
- K. Yamamoto, Structure polynomial of Latin rectangles and its application to a combinatorial problem, Memoirs of the Faculty of Science, Kyusyu University, Series A, 10 (1956), 1-13. [Annotated scanned copy]
-
a[ n_ ] := a[ n ]=(2n-5)a[ n-1 ]-(n-1)(n-4)a[ n-2 ]-(n-1)(n-2)a[ n-3 ]; a[ 0 ]=1; a[ 1 ]=-3; a[ 2 ]=5; Table[ a[ n ], {n, 0, 24} ] (* Typo fixed by Vaclav Kotesovec, Mar 20 2014 *)
Showing 1-10 of 12 results.
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