The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A223882 Number of n X 2 0..2 arrays with row sums unimodal and column sums inverted unimodal. 1
 9, 81, 564, 3298, 17048, 80412, 353485, 1469903, 5845411, 22414731, 83409546, 302722400, 1075880306, 3756503134, 12919764299, 43865509013, 147290172421, 489846413077, 1615582428816, 5289834522606, 17210293320924, 55679866275376 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A223885. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 17*a(n-1) - 126*a(n-2) + 534*a(n-3) - 1425*a(n-4) + 2481*a(n-5) - 2816*a(n-6) + 2008*a(n-7) - 816*a(n-8) + 144*a(n-9). Empirical g.f.: x*(9 - 72*x + 321*x^2 - 890*x^3 + 1617*x^4 - 1936*x^5 + 1480*x^6 - 672*x^7 + 144*x^8) / ((1 - x)^3*(1 - 2*x)^4*(1 - 3*x)^2). - Colin Barker, Aug 24 2018 EXAMPLE Some examples for n=3: ..0..1....0..0....1..1....0..1....0..0....1..2....0..0....0..1....0..2....2..2 ..0..2....1..2....2..2....2..0....1..0....2..2....0..0....0..2....2..2....0..2 ..2..0....2..2....0..0....1..1....1..2....0..2....0..0....1..1....1..1....0..1 CROSSREFS Cf. A223885. Sequence in context: A196986 A293889 A218268 * A267961 A213297 A272243 Adjacent sequences:  A223879 A223880 A223881 * A223883 A223884 A223885 KEYWORD nonn AUTHOR R. H. Hardin, Mar 28 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 29 21:32 EST 2021. Contains 349416 sequences. (Running on oeis4.)