# [seqfan] Re: Parking lot for bad drivers

Rob Pratt Rob.Pratt at sas.com
Wed Jul 15 22:41:54 CEST 2015

```At Neil's request, I created a new entry (will be http://oeis.org/A260090).  I described it in terms of attacking kings on a chessboard and conjectured a formula.

-----Original Message-----
From: Rob Pratt
Sent: Wednesday, July 15, 2015 11:29 AM
To: Sequence Fanatics Discussion list
Subject: RE: [seqfan] Re: Parking lot for bad drivers

And here’s a less trivial 26-car solution:

XX_XX_XX
________
XX_XX_XX
________
XX_XX_X_
_______X
X_X_X___
X_X_X_XX

For n in 1,...,8, I get the following, which is not in OEIS:
1, 2, 4, 8, 12, 16, 21, 26

-----Original Message-----
From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of APPLEGATE, DAVID L (DAVID L)
Sent: Wednesday, July 15, 2015 10:54 AM
To: Sequence Fanatics Discussion list
Subject: [seqfan] Re: Parking lot for bad drivers

I wonder if I misunderstand the problem as well - as I understand the problem, there's a trivial 24-car solution for the 8x8 lot:

XX_XX_XX
________
XX_XX_XX
________
XX_XX_XX
________
XX_XX_XX
________

David Applegate

-----Original Message-----
From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Rob Pratt
Sent: Wednesday, July 15, 2015 10:45 AM
To: Sequence Fanatics Discussion list
Subject: [seqfan] Re: Parking lot for bad drivers

Sorry, I just realized that I misinterpreted your problem to mean no three in a row, so A181018 provides only an upper bound.

-----Original Message-----
From: Rob Pratt
Sent: Wednesday, July 15, 2015 10:42 AM
To: 'Sequence Fanatics Discussion list'
Subject: RE: [seqfan] Parking lot for bad drivers

https://oeis.org/A181018

-----Original Message-----
From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Dale Gerdemann
Sent: Wednesday, July 15, 2015 6:22 AM
To: Sequence Fanatics Discussion list
Subject: [seqfan] Parking lot for bad drivers

Hello seqfans,

Here's a puzzle from p. 39 of "Let's be Less Stupid" by Patricia Marx:

At the parking lot for bad drivers, you are not allowed to park in a spot that is next to two occupied spots. In other words, no three cars can be contiguous--vertically, horizontally, or diagonally. ... How many cars can the lot fit.

As an example, the book shows an 8x8 "parking lot" (looks like a
chessboard) and gives a solution fitting 16 cars into this lot.

Is this in the OEIS?

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```