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 A223392 Number of 3Xn 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 0
 11, 121, 388, 4794, 40416, 375698, 4128762, 41424210, 415135608, 4912230456, 49929186692, 536801738054, 5986390459865, 67884672672695 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 1 of A223391 LINKS EXAMPLE Some solutions for n=3 ..1..0..2....2..1..1....2..0..1....2..0..2....2..1..2....1..0..2....1..1..2 ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..0..0....1..0..1 ..2..1..2....2..1..2....0..1..2....0..1..2....0..0..1....2..1..2....2..0..2 CROSSREFS Sequence in context: A240942 A216131 A338784 * A262468 A221964 A223640 Adjacent sequences:  A223389 A223390 A223391 * A223393 A223394 A223395 KEYWORD nonn AUTHOR R. H. Hardin Mar 19 2013 STATUS approved

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Last modified June 27 10:04 EDT 2022. Contains 354896 sequences. (Running on oeis4.)