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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A281061 Number of 6Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1

%I

%S 0,468,4988,10112,22106,46610,87995,159317,282552,495655,864369,

%T 1501627,2601791,4498333,7762266,13369326,22983871,39440039,67556367,

%U 115513187,197179026,336035590,571793109,971529387,1648428839,2793279473

%N Number of 6Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%C Row 6 of A281056.

%H R. H. Hardin, <a href="/A281061/b281061.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>19

%e Some solutions for n=4

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

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

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

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

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

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

%Y Cf. A281056.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jan 13 2017

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