A223220 - OEIS

A223220

Number of nX1 0..1 arrays with all rows and columns having a nonnegative second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative

2, 4, 5, 11, 19, 37, 68, 137, 261, 547, 1047, 2085, 4158, 8483, 16466, 33212, 66193, 131898, 263948, 527527, 1050219, 2116671, 4211442, 8401051, 16832288, 33765064, 67162966, 134559866, 269065487, 537669433, 1075891821, 2151469377, 4297450870

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OFFSET

1,1

COMMENTS

Column 1 of A223227

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..122

EXAMPLE

All solutions for n=3

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

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

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