The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A223653 Number of 3Xn 0..1 arrays with all rows having a nonnegative second derivative, and all and 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 1
 3, 9, 9, 35, 77, 207, 513, 1415, 4009, 12499, 37577, 99863, 300723, 949821, 2565811, 7925175, 23158917, 68824353, 207493163, 617410067, 1841509697, 5611469021, 16589242023, 49212663699, 148570250829, 449163990819, 1326001156759 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 1 of A223652 LINKS R. H. Hardin, Table of n, a(n) for n = 1..38 EXAMPLE Some solutions for n=3 ..0..0..1....0..0..0....1..1..1....1..1..1....1..1..1....1..1..1....1..0..0 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0 ..1..1..1....1..1..1....0..0..0....1..0..1....0..0..1....1..1..1....1..1..1 CROSSREFS Sequence in context: A223576 A125824 A203558 * A351929 A238912 A038227 Adjacent sequences: A223650 A223651 A223652 * A223654 A223655 A223656 KEYWORD nonn AUTHOR R. H. Hardin Mar 25 2013 STATUS approved

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

Last modified April 22 21:44 EDT 2024. Contains 371906 sequences. (Running on oeis4.)