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 1-5 of 5 results.

A293087 T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally or antidiagonally adjacent to some 0 two less than the number of 0's adjacent to some 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 5, 1, 0, 0, 23, 53, 10, 0, 1, 124, 486, 498, 60, 0, 3, 518, 4091, 8108, 4013, 304, 0, 10, 2103, 32070, 125848, 126903, 31689, 1420, 0, 24, 8304, 246852, 1900201, 3786544, 1955375, 246743, 6312, 0, 60, 32561, 1897509, 28709764
Offset: 1

Views

Author

R. H. Hardin, Sep 30 2017

Keywords

Comments

Table starts
.0.....0........0..........0.............0................1..................3
.0.....0........5.........23...........124..............518...............2103
.0.....1.......53........486..........4091............32070.............246852
.0....10......498.......8108........125848..........1900201...........28709764
.0....60.....4013.....126903.......3786544........112687158.........3370860734
.0...304....31689....1955375.....114271723.......6736259130.......400400301913
.0..1420...246743...30064393....3464680837.....405651046593.....48001754870966
.0..6312..1915490..462569756..105517939849...24578475941654...5797084510052322
.0.27167.14853287.7127871677.3226317873349.1496865603233666.704256987414278983

Examples

			Some solutions for n=4, k=4
..0..0..1..0. .0..0..0..0. .0..0..0..0. .0..0..1..1. .1..1..0..0
..0..0..0..0. .1..0..0..0. .0..0..0..0. .0..1..1..1. .1..1..0..0
..1..1..0..1. .1..0..0..1. .1..1..0..1. .0..0..0..0. .0..0..0..1
..0..0..1..1. .0..0..0..0. .0..0..1..0. .0..1..0..0. .0..0..1..0
		

Crossrefs

Row 1 is A286209.

A293100 T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally, diagonally or antidiagonally adjacent to some 0 two less than the number of 0's adjacent to some 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 9, 5, 0, 0, 42, 48, 30, 0, 1, 150, 567, 554, 126, 0, 3, 596, 3619, 8088, 3334, 520, 0, 10, 2220, 29952, 114318, 115870, 30837, 2088, 0, 24, 8376, 205195, 1676740, 3125547, 1710994, 202363, 8192, 0, 60, 31959, 1668655, 24773296
Offset: 1

Views

Author

R. H. Hardin, Sep 30 2017

Keywords

Comments

Table starts
.0.....0........0..........0.............0................1..................3
.0.....0........9.........42...........150..............596...............2220
.0.....5.......48........567..........3619............29952.............205195
.0....30......554.......8088........114318..........1676740...........24773296
.0...126.....3334.....115870.......3125547.........95603353.........2728695681
.0...520....30837....1710994......96199260.......5589631828.......328979478088
.0..2088...202363...25504769....2804027631.....331401441383.....38469698642410
.0..8192..1733660..383909610...85892871786...19865025530414...4665971856266714
.0.32083.12139768.5821195059.2579471093496.1200437139032383.560706154294046909

Examples

			Some solutions for n=4, k=4
..0..0..0..0. .0..0..0..1. .0..1..1..0. .1..1..0..1. .1..1..0..0
..1..0..0..0. .1..1..0..0. .1..0..0..1. .0..1..0..1. .0..1..1..0
..1..1..0..1. .1..0..1..0. .1..0..1..0. .0..0..1..0. .1..1..0..0
..0..0..1..0. .0..1..0..1. .0..1..0..0. .0..0..0..1. .1..0..0..0
		

Crossrefs

Column 2 is A286973.
Row 1 is A286209.

A289651 T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally, antidiagonally or vertically adjacent to some 0 two less than the number of 0's adjacent to some 1.

Original entry on oeis.org

0, 0, 0, 0, 2, 0, 0, 11, 11, 0, 0, 44, 61, 44, 0, 1, 170, 607, 607, 170, 1, 3, 642, 3160, 8554, 3160, 642, 3, 10, 2421, 31271, 121162, 121162, 31271, 2421, 10, 24, 9142, 183390, 1756800, 2662095, 1756800, 183390, 9142, 24, 60, 34572, 1714758, 25760875
Offset: 1

Views

Author

R. H. Hardin, Jul 09 2017

Keywords

Comments

Table starts
..0.....0........0..........0.............0................1..................3
..0.....2.......11.........44...........170..............642...............2421
..0....11.......61........607..........3160............31271.............183390
..0....44......607.......8554........121162..........1756800...........25760875
..0...170.....3160.....121162.......2662095.........98170524.........2439241607
..1...642....31271....1756800......98170524.......5675111511.......332113863074
..3..2421...183390...25760875....2439241607.....332113863074.....35072966294346
.10..9142..1714758..382162921...85298181531...19700973655406...4615203834449304
.24.34572.10957160.5717697619.2290353406298.1179502836506537.519140871714574338

Examples

			Some solutions for n=4, k=4
..1..0..0..0. .1..0..0..0. .0..1..1..0. .0..1..0..0. .1..0..0..1
..1..1..1..0. .0..1..0..1. .0..0..1..0. .1..1..0..1. .0..1..0..1
..1..0..1..0. .0..1..1..0. .0..1..1..1. .0..1..0..1. .0..1..1..0
..0..0..1..0. .0..1..0..1. .0..1..0..0. .0..1..0..0. .0..0..1..0
		

Crossrefs

Column 1 is A286209.

A286979 T(n,k) = Number of n X k 0..1 arrays with the number of 1's horizontally or vertically adjacent to some 0 two less than the number of 0's adjacent to some 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 5, 5, 0, 0, 30, 50, 30, 0, 1, 126, 538, 538, 126, 1, 3, 520, 3932, 8270, 3932, 520, 3, 10, 2088, 32253, 123706, 123706, 32253, 2088, 10, 24, 8192, 238532, 1853532, 3584756, 1853532, 238532, 8192, 24, 60, 32083, 1875212, 27938670
Offset: 1

Views

Author

R. H. Hardin, May 17 2017

Keywords

Comments

Table starts
..0.....0........0..........0.............0................1..................3
..0.....0........5.........30...........126..............520...............2088
..0.....5.......50........538..........3932............32253.............238532
..0....30......538.......8270........123706..........1853532...........27938670
..0...126.....3932.....123706.......3584756........108110791.........3229944132
..1...520....32253....1853532.....108110791.......6394436704.......382399996325
..3..2088...238532...27938670....3229944132.....382399996325.....45587718323826
.10..8192..1875212..424161696...98063836816...23061514189084...5491408595796062
.24.32083.14222474.6473516290.2979455186170.1399727072882973.665386690317576640

Examples

			Some solutions for n=4, k=4
..0..1..1..1. .1..0..0..1. .0..0..0..0. .1..0..0..1. .0..1..1..1
..0..0..0..1. .1..0..0..1. .0..1..1..0. .0..1..0..1. .0..0..1..0
..1..0..0..0. .0..0..1..1. .0..1..1..0. .0..0..1..1. .0..1..0..1
..1..0..0..0. .1..0..0..0. .1..0..0..1. .1..0..0..0. .0..1..0..0
		

Crossrefs

Column 1 is A286209.

A307796 Number T(n,k) of binary words of length n such that k is the difference of numbers of occurrences of subword 101 and subword 010; triangle T(n,k), n>=0, -floor(n/3)<=k<=floor(n/3), read by rows.

Original entry on oeis.org

1, 2, 4, 1, 6, 1, 2, 12, 2, 6, 20, 6, 1, 12, 38, 12, 1, 3, 28, 66, 28, 3, 10, 56, 124, 56, 10, 1, 24, 119, 224, 119, 24, 1, 4, 60, 236, 424, 236, 60, 4, 15, 134, 481, 788, 481, 134, 15, 1, 42, 304, 950, 1502, 950, 304, 42, 1, 5, 114, 656, 1902, 2838, 1902, 656, 114, 5
Offset: 0

Views

Author

Alois P. Heinz, Apr 29 2019

Keywords

Examples

			T(8,2) = 10: 01101101, 10101101, 10110101, 10110110, 10110111, 10111011, 10111101, 11011011, 11011101, 11101101.
T(8,-2) = 10: 00010010, 00100010, 00100100, 01000010, 01000100, 01001000, 01001001, 01001010, 01010010, 10010010.
T(9,3)  = 1: 101101101.
T(9,-3) = 1: 010010010.
Triangle T(n,k) begins:
  :                      1                   ;
  :                      2                   ;
  :                      4                   ;
  :                1,    6,   1              ;
  :                2,   12,   2              ;
  :                6,   20,   6              ;
  :           1,  12,   38,  12,   1         ;
  :           3,  28,   66,  28,   3         ;
  :          10,  56,  124,  56,  10         ;
  :      1,  24, 119,  224, 119,  24,  1     ;
  :      4,  60, 236,  424, 236,  60,  4     ;
  :     15, 134, 481,  788, 481, 134, 15     ;
  :  1, 42, 304, 950, 1502, 950, 304, 42, 1  ;
		

Crossrefs

Columns k=0-2 give: A164146, A284449, A286209.
Row sums give A000079.
T(3n-4,n-2) gives A000217 for n >= 3.

Programs

  • Maple
    b:= proc(n, t, h) option remember; `if`(n=0, 1, expand(
          `if`(h=3, 1/x, 1)*b(n-1, [1, 3, 1][t], 2)+
          `if`(t=3, x, 1)*b(n-1, 2, [1, 3, 1][h])))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=-iquo(n, 3)..iquo(n, 3)))(b(n, 1$2)):
    seq(T(n), n=0..15);
  • Mathematica
    b[n_, t_, h_] := b[n, t, h] = If[n == 0, 1, Expand[If[h == 3, 1/x, 1]* b[n-1, {1, 3, 1}[[t]], 2] + If[t == 3, x, 1]*b[n-1, 2, {1, 3, 1}[[h]]]]];
    T[n_] := Table[Coefficient[#, x, i], {i, -Quotient[n, 3], Quotient[n, 3]}]& @ b[n, 1, 1];
    Table[T[n], {n, 0, 15}] // Flatten (* Jean-François Alcover, May 08 2019, after Alois P. Heinz *)

Formula

T(n,k) = T(n,-k).
Sum_{k = -floor(n/3)..floor(n/3)} T(n,k) * k^2/2 = A057711(n-2) for n > 1.
Showing 1-5 of 5 results.