login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A296327 T(n,k)=Number of nXk 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 neighboring 1s. 7
1, 1, 1, 1, 3, 1, 1, 5, 5, 1, 1, 8, 11, 8, 1, 1, 15, 23, 23, 15, 1, 1, 26, 54, 61, 54, 26, 1, 1, 45, 122, 185, 185, 122, 45, 1, 1, 80, 278, 562, 853, 562, 278, 80, 1, 1, 140, 634, 1677, 3569, 3569, 1677, 634, 140, 1, 1, 245, 1438, 4998, 14691, 20088, 14691, 4998, 1438, 245, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Table starts

.1...1....1.....1......1.......1........1.........1...........1............1

.1...3....5.....8.....15......26.......45........80.........140..........245

.1...5...11....23.....54.....122......278.......634........1438.........3274

.1...8...23....61....185.....562.....1677......4998.......14968........44818

.1..15...54...185....853....3569....14691.....62193......261763......1099727

.1..26..122...562...3569...20088...112235....643541.....3666933.....20890748

.1..45..278..1677..14691..112235...850404...6660799....51754039....401363520

.1..80..634..4998..62193..643541..6660799..72224019...769931084...8196375877

.1.140.1438.14968.261763.3666933.51754039.769931084.11207386103.163095751500

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..449

FORMULA

Empirical for column k:

k=1: a(n) = a(n-1)

k=2: a(n) = a(n-1) +2*a(n-3) +a(n-5)

k=3: a(n) = 2*a(n-1) -a(n-2) +4*a(n-3) -2*a(n-4) +4*a(n-5) -3*a(n-6) +2*a(n-7) -a(n-8)

k=4: [order 14]

k=5: [order 40]

k=6: [order 83]

EXAMPLE

Some solutions for n=5 k=4

..1..1..0..0. .1..1..0..1. .0..0..0..0. .0..1..1..0. .0..1..0..0

..1..0..0..0. .1..0..1..1. .0..0..0..0. .0..1..0..0. .1..1..0..0

..0..0..0..0. .0..0..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0

..0..0..1..1. .0..0..1..0. .0..1..0..1. .0..0..0..1. .1..1..0..1

..0..0..1..0. .0..1..1..0. .0..1..1..0. .0..0..1..1. .1..0..1..1

CROSSREFS

Column 2 is A193147(n+1).

Sequence in context: A228356 A253670 A137897 * A296541 A056152 A171229

Adjacent sequences:  A296324 A296325 A296326 * A296328 A296329 A296330

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Dec 10 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 9 14:04 EDT 2020. Contains 333353 sequences. (Running on oeis4.)