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.

Showing 1-4 of 4 results.

A264550 T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change -1,1 -1,2 1,0 or 0,-1.

Original entry on oeis.org

0, 1, 1, 1, 2, 0, 1, 6, 5, 0, 1, 16, 16, 10, 1, 3, 40, 36, 45, 21, 0, 3, 96, 172, 216, 133, 44, 0, 4, 240, 764, 1528, 1160, 400, 93, 1, 6, 608, 2728, 11728, 14852, 4640, 1204, 196, 0, 9, 1536, 9880, 66372, 163744, 105081, 23140, 3561, 413, 0, 12, 3840, 38818, 403920
Offset: 1

Views

Author

R. H. Hardin, Nov 17 2015

Keywords

Comments

Table starts
.0...1.....1.......1.........1...........3.............3...............4
.1...2.....6......16........40..........96...........240.............608
.0...5....16......36.......172.........764..........2728............9880
.0..10....45.....216......1528.......11728.........66372..........403920
.1..21...133....1160.....14852......163744.......1573479........16103502
.0..44...400....4640....105081.....1994830......29691127.......480994368
.0..93..1204...23140....813473....25172836.....591482528.....15554895920
.1.196..3561..110592...6587227...316806958...11959837149....510948245264
.0.413.10554..501828..50597392..3939510885..234588752099..16034698666868
.0.870.31493.2390752.392445418.49105816488.4630258704238.508458281055496

Examples

			Some solutions for n=4 k=4
..1..2..5..6..7....1..2..3..4..7....1..2..3..7..8....1..5..3..6..8
..0.10..8..3..4....0.10..8.11.12....0.10.11.12..4....0..7..2.12..4
.11.12.15.14..9....5..6.13.17..9....5..6.13.17..9...11.15.13.14..9
.16.20.18.13.23...16.20.18.21.14...16.20.18.21.14...10.20.18.22.23
.21.22.17.24.19...15.22.23.24.19...15.22.23.24.19...21.16.17.24.19
		

Crossrefs

Row 1 is A080013(n+1).

Formula

Empirical for column k:
k=1: a(n) = a(n-3)
k=2: a(n) = 2*a(n-1) +a(n-4)
k=3: [order 15]
k=4: [order 10] for n>11
k=5: [order 84]
Empirical for row n:
n=1: a(n) = a(n-2) +a(n-3) +a(n-4) -a(n-6)
n=2: a(n) = 2*a(n-1) +8*a(n-4)
n=3: [order 70]
n=4: [order 56] for n>59

A264676 T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change -1,-1 1,0 -1,-2 -2,-2 or 0,1.

Original entry on oeis.org

0, 1, 1, 1, 2, 0, 1, 10, 9, 0, 1, 29, 34, 19, 1, 3, 75, 123, 145, 44, 0, 3, 201, 748, 890, 603, 108, 0, 4, 588, 3698, 9205, 6851, 2417, 264, 1, 6, 1700, 17443, 88687, 123222, 43131, 9976, 649, 0, 9, 4785, 84737, 714235, 2025372, 1449467, 291315, 40825, 1573, 0, 12
Offset: 1

Views

Author

R. H. Hardin, Nov 20 2015

Keywords

Comments

Table starts
.0....1......1........1...........1.............3..............3
.1....2.....10.......29..........75...........201............588
.0....9.....34......123.........748..........3698..........17443
.0...19....145......890........9205.........88687.........714235
.1...44....603.....6851......123222.......2025372.......29875350
.0..108...2417....43131.....1449467......43095017.....1095840260
.0..264...9976...291315....17406354.....918298857....40765995197
.1..649..40825..1980287...209749118...19297801298..1494347569074
.0.1573.166985.13199209..2503676777..404856272120.54204721906375
.0.3837.684253.88670692.29934965340.8489260394876

Examples

			Some solutions for n=4 k=4
..6..8..1..2..3....7..8..1..2..3...12..8..1..2..3...12.13..1..2..3
..0..5.14..7..4....0.13..6.14..4....0..5..6..7..4....0.18.19..7..4
.16.10.24.19..9....5.23.24.12..9...17.18.24.19..9....5..6.24..8..9
.21.11.12.13.18...10.11.16.17.18...10.11.16.13.14...10.11.16.17.14
.15.20.17.22.23...15.20.21.22.19...15.20.21.22.23...15.20.21.22.23
		

Crossrefs

Row 1 is A080013(n+1).

Formula

Empirical for column k:
k=1: a(n) = a(n-3)
k=2: a(n) = 2*a(n-1) +a(n-3) +3*a(n-4) +2*a(n-5) -a(n-6) +4*a(n-7) -a(n-8) -a(n-10)
k=3: [order 15]
k=4: [order 26] for n>27
Empirical for row n:
n=1: a(n) = a(n-2) +a(n-3) +a(n-4) -a(n-6)
n=2: [order 9]
n=3: [order 70]
n=4: [order 81] for n>86

A264422 T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change 0,1 2,2 1,0 -1,2 -2,-1 or -1,-1.

Original entry on oeis.org

0, 2, 1, 0, 3, 1, 0, 12, 20, 1, 4, 37, 96, 85, 1, 0, 119, 499, 529, 351, 3, 0, 385, 2681, 7311, 4843, 1462, 3, 8, 1252, 15088, 101862, 137584, 44264, 6021, 4, 0, 4061, 86469, 1103666, 4023076, 2486429, 352713, 25188, 6, 0, 13166, 479787, 13805196, 95946259
Offset: 1

Views

Author

R. H. Hardin, Nov 12 2015

Keywords

Comments

Table starts
.0......2.........0...........0............4............0............0
.1......3........12..........37..........119..........385.........1252
.1.....20........96.........499.........2681........15088........86469
.1.....85.......529........7311.......101862......1103666.....13805196
.1....351......4843......137584......4023076.....95946259...2486418295
.3...1462.....44264.....2486429....147984724...7577203142.396849643846
.3...6021....352713....40217261...5498758183.577598946184
.4..25188...2840274...681146169.201733617932
.6.104870..23795758.11846231201
.9.437164.197390196

Examples

			Some solutions for n=4 k=4
..6..7..8..2..3....6..7..8..2..3....6..0..8..9..3....6.12.13.14..3
..0..1.13.19..4...11..1.13.19..4...16..1..2..7..4....0..1..2.19..4
..5.17.18.12..9....5.17..0.12..9....5.17.11.19.13...16.10..7..8..9
.21.22.20.24.14...10.22.16.24.14...10.22.23.24.14...21.11..5.24.22
.15.16.10.11.23...15.20.21.18.23...15.20.21.18.12...15.20.17.18.23
		

Crossrefs

Column 1 is A080013(n+1).

Formula

Empirical for column k:
k=1: a(n) = a(n-2) +a(n-3) +a(n-4) -a(n-6)
k=2: [order 56]
k=3: [order 70]
Empirical for row n:
n=1: a(n) = 2*a(n-3)
n=2: a(n) = 3*a(n-1) +a(n-3) +5*a(n-4) +a(n-7)
n=3: [order 33]
n=4: [order 16] for n>18

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).
Showing 1-4 of 4 results.