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.

Previous Showing 21-26 of 26 results.

A154659 Number of permutations of length n within distance 10.

Original entry on oeis.org

1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 402796800, 3770686080, 33187593600, 278598101040, 2261952938160, 17986137205800, 141564484858104, 1112444773251726, 8787513806478134, 70146437009397871, 568128719132038153, 4647312969412825372
Offset: 0

Views

Author

Torleiv Kløve, Jan 13 2009

Keywords

Crossrefs

Extensions

More terms from Alois P. Heinz, Jan 13 2014

A188962 T(n,k)=Number of nXk array permutations with each element moved by a city block distance of no more than three.

Original entry on oeis.org

1, 2, 2, 6, 24, 6, 24, 720, 720, 24, 78, 24024, 229080, 24024, 78, 230, 570050, 75764664, 75764664, 570050, 230, 675, 12702057, 17316382188, 251096032912, 17316382188, 12702057, 675, 2069, 298167456, 3909049448304, 573780546403024
Offset: 1

Views

Author

R. H. Hardin Apr 14 2011

Keywords

Comments

Table starts
....1.........2.............6..............24..............78...........230
....2........24...........720...........24024..........570050......12702057
....6.......720........229080........75764664.....17316382188.3909049448304
...24.....24024......75764664....251096032912.573780546403024
...78....570050...17316382188.573780546403024
..230..12702057.3909049448304
..675.298167456
.2069

Examples

			Some solutions for 5X3
..0..5..1....0..5..1....0..5..1....0..5..1....0..5..1....0..5..1....0..5..1
..6..3.10....6..3.10....6..3.10....6..3..7....6..3..7....6..3..7....6..3..7
..7..2.14...13..7.11....9.14..7....8..2.13...10..2.11....4.14..2...11.13..2
.11..4..9....8..4..2....8..4..2...14..4..9...13..8..4....8..9.10...14..4.10
.13..8.12...12.14..9...13.11.12...11.12.10...12.14..9...11.13.12...12..9..8
		

Crossrefs

Column 1 is A002526

A376743 Number of permutations (p(1),p(2),...,p(n)) of (1,2,...,n) such that p(i)-i is in {-2,-1,4} for all i=1,...,n.

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 5, 5, 6, 8, 11, 15, 25, 35, 46, 61, 85, 125, 175, 245, 341, 470, 650, 925, 1300, 1810, 2521, 3520, 4915, 6880, 9640, 13476, 18801, 26251, 36721, 51346, 71776, 100335, 140210, 195886, 273813, 382821, 535105, 747850, 1045220
Offset: 0

Views

Author

Michael A. Allen, Oct 03 2024

Keywords

Comments

Other sequences related to strongly restricted permutations pi(i) of i in {1,..,n} along with the sets of allowed p(i)-i (containing at least 3 elements): A000045 {-1,0,1}, A189593 {-1,0,2,3,4,5,6}, A189600 {-1,0,2,3,4,5,6,7}, A006498 {-2,0,2}, A080013 {-2,1,2}, A080014 {-2,0,1,2}, A033305 {-2,-1,1,2}, A002524 {-2,-1,0,1,2}, A080000 {-2,0,3}, A080001 {-2,1,3}, A080004 {-2,0,1,3}, A080002 {-2,2,3}, A080005 {-2,0,2,3}, A080008 {-2,1,2,3}, A080011 {-2,0,1,2,3}, A079999 {-2,-1,3}, A080003 {-2,-1,0,3}, A080006 {-2,-1,1,3}, A080009 {-2,-1,0,1,3}, A080007 {-2,-1,2,3}, A080010 {-2,-1,0,2,3}, A080012 {-2,-1,1,2,3}, A072827 {-2,-1,0,1,2,3}, A224809 {-2,0,4}, A189585 {-2,0,1,3,4}, A189581 {-2,-1,0,3,4}, A072850 {-2,-1,0,1,2,3,4}, A189587 {-2,0,1,3,4,5}, A189588 {-2,-1,0,3,4,5}, A189594 {-2,0,1,3,4,5,6}, A189595 {-2,-1,0,3,4,5,6}, A189601 {-2,0,1,3,4,5,6,7}, A189602 {-2,-1,0,3,4,5,6,7}, A224811 {-2,0,8}, A224812 {-2,0,10}, A224813 {-2,0,12}, A006500 {-3,0,3}, A079981 {-3,1,3}, A079983 {-3,0,1,3}, A079982 {-3,2,3}, A079984 {-3,0,2,3}, A079988 {-3,1,2,3}, A079989 {-3,0,1,2,3}, A079986 {-3,-1,1,3}, A079992 {-3,-1,0,1,3}, A079987 {-3,-1,2,3}, A079990 {-3,-1,0,2,3}, A079993 {-3,-1,1,2,3}, A079985 {-3,-2,2,3}, A079991 {-3,-2,0,2,3}, A079996 {-3,-2,0,1,2,3}, A079994 {-3,-2,1,2,3}, A079997 {-3,-2, -1,1,2,3}, A002526 {-3,-2,-1,0,1,2,3}, A189586 {-3,0,1,2,4}, A189583 {-3,-1,0,2,4}, A189582 {-3,-2,0,1,4}, A189584 {-3,-2,-1,0,4}, A189589 {-3,0,1,2,4,5}, A189590 {-3,-1,0,2,4,5}, A189591 {-3,-2,1,4,5}, A189592 {-3,-2,-1,0,4,5}, A224810 {-3,0,6}, A189596 {-3,0,1,2,4,5,6}, A189597 {-3,-1,0,2,4,5,6}, A189598 {-3,-2,0,1,4,5,6}, A189599 {-3,-2,-1,0,4,5,6}, A224814 {-3,0,9}, A031923 {-4,0,4}, A072856 {-4,-3, -2,-1,0,1,2,3,4}, A224815 {-4,0,8}, A154654 {-5,-4,-3,-2,-1,0,1,2,3,4,5}, A154655 {-6,-5,-4,-3, -2,-1,0,1,2,3,4,5,6}.
[Keyword "less", because this comment should be moved to the Index to the OEIS, it is not appropriate here. - N. J. A. Sloane, Oct 25 2024]

References

  • D. H. Lehmer, Permutations with strongly restricted displacements. Combinatorial theory and its applications, II (Proc. Colloq., Balatonfured, 1969), North-Holland, Amsterdam, 1970, pp. 755-770.

Crossrefs

See comments for other sequences related to strongly restricted permutations.

Programs

  • Mathematica
    CoefficientList[Series[(1 - x^3 - x^4 - x^6 + x^9)/(1 - x^3 - x^4 - x^5 - 2*x^6 - x^7 + 2*x^9 + 2*x^10 + x^12 - x^15),{x,0,49}],x]
    LinearRecurrence[{0, 0, 1, 1, 1, 2, 1, 0, -2, -2, 0, -1, 0, 0, 1}, {1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 5, 5, 6, 8}, 50]

Formula

a(n) = a(n-3) + a(n-4) + a(n-5) + 2*a(n-6) + a(n-7) - 2*a(n-9) - 2*a(n-10) - a(n-12) + a(n-15).
G.f.: (1 - x^3 - x^4 - x^6 + x^9)/(1 - x^3 - x^4 - x^5 - 2*x^6 - x^7 + 2*x^9 + 2*x^10 + x^12 - x^15).

A188498 Number of permutations p on the set [n] with the properties that abs(p(i)-i) <= 3 for all i, p(1) <= 2, and p(j) >= 2 for j=3,4.

Original entry on oeis.org

0, 1, 2, 3, 8, 30, 102, 308, 905, 2744, 8473, 26112, 79924, 244204, 747160, 2288521, 7009458, 21461803, 65704200, 201162258, 615922714, 1885853660, 5774072225, 17678809840, 54128358209, 165728860112, 507424764216, 1553620027784, 4756831354752
Offset: 0

Views

Author

N. J. A. Sloane, Apr 01 2011

Keywords

Comments

a(n) is also the permanent of the n X n matrix that has ones on its diagonal, ones on its three superdiagonals (with the exception of zeros in the (1,3) and (1,4)-entries), ones on its three subdiagonals (with the exception of zeros in the (3,1) and (4,1)-entries), and is zero elsewhere.
This is row 13 of Kløve's Table 3.

Programs

  • Maple
    with(LinearAlgebra):
    A188498:= n-> `if` (n=0, 0, Permanent (Matrix (n, (i, j)->
                  `if` (abs(j-i)<4 and [i, j]<>[1, 3] and [i, j]<>[1, 4] and [i, j]<>[3, 1] and [i, j]<>[4, 1], 1, 0)))):
    seq (A188498(n), n=0..20);
  • Mathematica
    a[n_] := Permanent[Table[If[Abs[j - i] < 4 && {i, j} != {1, 3} && {i, j} != {1, 4} && {i, j} != {3, 1} && {i, j} != {4, 1}, 1, 0], {i, 1, n}, {j, 1, n}]]; a[1] = 1; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 20}] (* Jean-François Alcover, Jan 07 2016, adapted from Maple *)
    CoefficientList[Series[-(x^10 + 2 x^9 + x^8 - 2 x^6 - 2 x^5 - 2 x^4 - 3 x^3 + x) / (x^14 + 2 x^13 + 2 x^11 + 4 x^10 - 2 x^9 - 10 x^8 - 16 x^7 - 2 x^6 + 8 x^5 + 10 x^4 + 2 x^2 + 2 x - 1), {x, 0, 33}], x] (* Vincenzo Librandi, Jan 07 2016 *)
  • PARI
    concat(0, Vec(-(x^10+2*x^9+x^8 -2*x^6-2*x^5-2*x^4 -3*x^3+x) / (x^14+2*x^13+2*x^11 +4*x^10-2*x^9-10*x^8 -16*x^7-2*x^6+8*x^5 +10*x^4+2*x^2+2*x-1) + O(x^40))) \\ Michel Marcus, Dec 12 2014

Formula

From Nathaniel Johnston, Apr 11 2011: (Start)
a(n) = A188497(n+1) - A188494(n).
a(n) = A002526(n-1) + A002526(n-2).
(End)
G.f.: -(x^10 + 2*x^9 + x^8 - 2*x^6 - 2*x^5 - 2*x^4 - 3*x^3 + x) / (x^14 + 2*x^13 + 2*x^11 + 4*x^10 - 2*x^9 - 10*x^8 - 16*x^7 - 2*x^6 + 8*x^5 + 10*x^4 + 2*x^2 + 2*x - 1).

Extensions

Name and comments edited, and a(12)-a(28) from Nathaniel Johnston, Apr 11 2011

A323799 Number of permutations p of [n] such that max_{j=1..n} |p(j)-j| = 3.

Original entry on oeis.org

0, 10, 47, 157, 503, 1669, 5472, 17531, 55135, 172134, 535510, 1660795, 5133470, 15826173, 48706210, 149721544, 459820058, 1411142937, 4328181110, 13269541967, 40669595890, 124617708274, 381776661185, 1169438884559, 3581781480980, 10969462410857, 33592685042253
Offset: 3

Views

Author

Alois P. Heinz, Jan 28 2019

Keywords

Examples

			a(4) = 10: 2341, 2431, 3241, 3421, 4123, 4132, 4213, 4231, 4312, 4321.
		

Crossrefs

Column k=3 of A130152.

Formula

G.f.: x^4 *(x^11+x^10-3*x^9+x^8+4*x^7-4*x^6-4*x^5-5*x^4+11*x^3+11*x^2-7*x-10) / ((x-1) *(x^5 -2*x^3 -2*x+1) *(x^13 +3*x^12 +3*x^11 +5*x^10 +9*x^9 +7*x^8 -3*x^7 -19*x^6 -21*x^5 -13*x^4 -3*x^3 -3*x^2-x+1)).
a(n) = A002526(n) - A002524(n).

A323800 Number of permutations p of [n] such that max_{j=1..n} |p(j)-j| = 4.

Original entry on oeis.org

0, 42, 274, 1227, 4833, 18827, 75693, 304900, 1212960, 4753020, 18410363, 70943107, 272701262, 1046410914, 4007815161, 15319362279, 58456445860, 222775782355, 848216866767, 3227396592600, 12273205919568, 46650941505906, 177252609519698, 673266690295879
Offset: 4

Views

Author

Alois P. Heinz, Jan 28 2019

Keywords

Crossrefs

Column k=4 of A130152.

Formula

a(n) = A072856(n) - A002526(n).
Previous Showing 21-26 of 26 results.