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 11-20 of 20 results.

A069419 Number of 5 X n binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 97, 5149, 217253, 8168645, 287275073, 9681281781
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A069420 Number of 6 X n binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 237, 28159, 2575297, 206458895
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A069421 Number of 7 X n binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 575, 151331, 29682643
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A069422 Number of 8 X n binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 1391, 806463, 337104939
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A069423 Number of n X 3 binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 19, 147, 907, 5149, 28159, 151331, 806463, 4280141, 22670199, 119955523, 634412111, 3354416225, 17734138519, 93751306327, 495600489243, 2619870168133, 13849199313235, 73209594712831, 386999645945759, 2045750897807901, 10814208630415211, 57165847109895879
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Formula

a(n) = A069378(n) - 2 * A069403(n). - Sean A. Irvine, Aug 23 2024
G.f.: x*(2*x^7-10*x^6+23*x^5-18*x^4-5*x^3+21*x^2-8*x-1) / ((x-1)*(x^2-3*x+1)*(2*x^5-4*x^4+x^3+9*x^2-7*x+1)). - Alois P. Heinz, Aug 23 2024

Extensions

More terms from Sean A. Irvine, Aug 23 2024

A069424 Number of n X 4 binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 65, 1231, 17339, 217253, 2575297, 29682643, 337104939, 3798244149, 42611591165, 476921965419, 5330934738199, 59545502975241, 664849480893793, 7421696282496891, 82838232515999423, 924548372982432205, 10318403957821437753, 115156011527942405255
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Formula

a(n) = A069379(n) - 2 * A069404(n). - Sean A. Irvine, Aug 23 2024

Extensions

More terms from Sean A. Irvine, Aug 23 2024

A069425 Number of n X 5 binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 211, 9539, 300651, 8168645, 206458895, 5022868187, 119647195507, 2816023729437, 65818825735031, 1532136293558119, 35579894275049831, 825082170362304285, 19117256012937548815, 442728846445605819023, 10249950234312030878755, 237262687880593853560805
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Formula

a(n) = A069380(n) - 2 * A069405(n). - Sean A. Irvine, Aug 23 2024

Extensions

More terms from Sean A. Irvine, Aug 23 2024

A069426 Number of n X 6 binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 665, 70679, 4927163, 287275073
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A069427 Number of n X 7 binary arrays with a path of adjacent 1's and no path of adjacent 0's from top row to bottom row.

Original entry on oeis.org

1, 2059, 509019, 77892523, 9681281781
Offset: 1

Views

Author

R. H. Hardin, Mar 22 2002

Keywords

Crossrefs

Cf. 2 X n A001047, n X 2 A034182, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

A098894 Values of k such that {s(1),...,s(k)} is a palindrome, where {s(1),s(2),...} is the fixed point of the substitutions 0->1 and 1->110.

Original entry on oeis.org

1, 2, 5, 8, 15, 22, 39, 56, 97, 138, 237, 336, 575, 814, 1391, 1968, 3361, 4754, 8117, 11480, 19599, 27718, 47319, 66920, 114241, 161562, 275805, 390048, 665855, 941662, 1607519, 2273376, 3880897, 5488418, 9369317
Offset: 1

Views

Author

John W. Layman, Nov 04 2004

Keywords

Comments

Superseeker suggests: (1) o.g.f. (1+x+x^2+x^3)/(1+2x-2x^2-x^3+x^4+x^5), (2) terms of odd index {1,5,15,39,...} give A034182 and (3) {a(n)+2} gives A082766, except for several initial terms.
Conjecture: partial sums of A152113. - Sean A. Irvine, Jul 14 2022

Examples

			Start with 1 and iterate the substitutions 0->1, 1->110 to get 1, 110, 1101101, 11011011101101110, 11011011101101110110110111011011101101101,... The initial terms from the beginning to the single quotes form palindromes: 1'1'011'011'1011011'1011011',..., of lengths 1,2,5,8,15,22,...
		

Crossrefs

Previous Showing 11-20 of 20 results.