A223391 - OEIS

A223391

T(n,k) is the number of (n+2) X k 0..2 arrays with all rows having a nonnegative second derivative, and all columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.

11, 121, 31, 388, 961, 105, 4794, 5450, 11025, 342, 40416, 188958, 120738, 116964, 1044, 375698, 4182458, 14855514, 2326103, 1089936, 3159, 4128762, 101698908, 1030363654, 993542957, 40102656, 9979281, 9735, 41424210, 2972878486, 80122222262, 208801521397, 53115687500, 663777212, 94770225, 28302

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..47

EXAMPLE

Table starts:

....11.......121.........388..........4794..........40416.........375698

....31.......961........5450........188958........4182458......101698908

...105.....11025......120738......14855514.....1030363654....80122222262

...342....116964.....2326103.....993542957...208801521397.49244499538437

..1044...1089936....40102656...53115687500.31140652265964

..3159...9979281...663777212.2791742360102

..9735..94770225.11304765020

.28302.801003204

.87129

Some solutions for n=1 and k=4:

..2..0..2..2....2..2..2..2....1..0..0..2....1..1..2..2....1..1..1..1

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

..2..2..0..1....1..0..0..2....2..1..1..1....2..2..0..0....2..2..1..2

CROSSREFS

Sequence in context: A081122 A004190 A089707 * A337707 A084969 A045592

Adjacent sequences: A223388 A223389 A223390 * A223392 A223393 A223394

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 19 2013

STATUS

approved