login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A210694 T(n,k)=Number of (n+1)X(n+1) -k..k symmetric matrices with every 2X2 subblock having sum zero 1
5, 13, 9, 25, 35, 17, 41, 91, 97, 33, 61, 189, 337, 275, 65, 85, 341, 881, 1267, 793, 129, 113, 559, 1921, 4149, 4825, 2315, 257, 145, 855, 3697, 10901, 19721, 18571, 6817, 513, 181, 1241, 6497, 24583, 62281, 94509, 72097, 20195, 1025, 221, 1729, 10657, 49575 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

...5....13.....25......41.......61.......85.......113.......145........181

...9....35.....91.....189......341......559.......855......1241.......1729

..17....97....337.....881.....1921.....3697......6497.....10657......16561

..33...275...1267....4149....10901....24583.....49575.....91817.....159049

..65...793...4825...19721....62281...164305....379793....793585....1531441

.129..2315..18571...94509...358061..1103479...2920695...6880121...14782969

.257..6817..72097..456161..2070241..7444417..22542017..59823937..143046721

.513.20195.281827.2215269.12030821.50431303.174571335.521638217.1387420489

Solutions are determined by the diagonal, extended with x(i,j) = (x(i,i)+x(j,j))/2 * (-1)^(i-j)

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..10000

FORMULA

T(n,k)=k^(n+1)+(k+1)^(n+1)

EXAMPLE

Some solutions for n=3 k=4

.-2..1.-3..0....0.-1..0..1....4..0..1.-1....2.-1.-1.-2....3.-2..1..0

..1..0..2..1...-1..2.-1..0....0.-4..3.-3...-1..0..2..1...-2..1..0.-1

.-3..2.-4..1....0.-1..0..1....1..3.-2..2...-1..2.-4..1....1..0.-1..2

..0..1..1..2....1..0..1.-2...-1.-3..2.-2...-2..1..1..2....0.-1..2.-3

CROSSREFS

cf. A179927

Column 1 is A000051(n+1)

Column 2 is A007689(n+1)

Column 3 is A074605(n+1)

Column 4 is A074611(n+1)

Column 5 is A074615(n+1)

Column 6 is A074619(n+1)

Column 7 is A074622(n+1)

Column 8 is A074624(n+1)

Row 1 is A001844

Row 2 is A005898

Row 3 is A008514

Row 4 is A008515

Row 5 is A008516

Row 6 is A036085

Row 7 is A036086

Row 8 is A036087

Sequence in context: A094474 A064109 A175484 * A298316 A299190 A156682

Adjacent sequences:  A210691 A210692 A210693 * A210695 A210696 A210697

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, with R. J. Mathar in the Sequence Fans Mailing List, Mar 30 2012

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 August 18 07:11 EDT 2019. Contains 326072 sequences. (Running on oeis4.)