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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A223952 Number of 5 X n 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing. 1

%I

%S 32,243,596,1062,1821,3115,5233,8564,13613,21017,31561,46194,66045,

%T 92439,126913,171232,227405,297701,384665,491134,620253,775491,960657,

%U 1179916,1437805,1739249,2089577,2494538,2960317,3493551,4101345,4791288,5571469

%N Number of 5 X n 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.

%C Row 5 of A223949.

%H R. H. Hardin, <a href="/A223952/b223952.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (2/15)*n^5 + (1/6)*n^4 + (23/6)*n^3 + (89/6)*n^2 + (1501/30)*n + 200 for n>3.

%F Conjectures from _Colin Barker_, Aug 24 2018: (Start)

%F G.f.: x*(32 + 51*x - 382*x^2 + 491*x^3 + 9*x^4 - 348*x^5 + 132*x^6 + 68*x^7 - 37*x^8) / (1 - x)^6.

%F a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>9.

%F (End)

%e Some solutions for n=3:

%e ..0..1..1....1..1..1....0..0..1....0..0..1....0..0..0....0..0..0....0..1..1

%e ..0..1..1....0..1..1....0..0..1....1..1..1....0..1..1....0..1..1....0..0..1

%e ..0..1..1....0..0..0....0..0..0....0..0..1....0..1..1....0..0..0....0..1..1

%e ..1..1..1....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..1..1

%e ..0..0..1....0..0..1....0..0..1....0..0..0....0..1..1....0..0..0....1..1..1

%Y Cf. A223949.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 29 2013

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 16:41 EST 2022. Contains 350611 sequences. (Running on oeis4.)