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!)
A218201 Hilltop maps: number of nX3 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..2 nX3 array 1
7, 59, 483, 3841, 30599, 243953, 1945103, 15508803, 123654745, 985923281, 7860958915, 62676962321, 499735676361, 3984490261291, 31769119935801, 253301405031061, 2019621630078545, 16102838151192633, 128391077151131153 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A218206

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 7*a(n-1) +6*a(n-2) +12*a(n-3) +10*a(n-4) +48*a(n-5) +9*a(n-6) +5*a(n-7) +13*a(n-8) +11*a(n-9) -51*a(n-10) -59*a(n-11) -48*a(n-12) -38*a(n-13) +13*a(n-14) +39*a(n-15) +33*a(n-16) +15*a(n-17) +5*a(n-18) -5*a(n-19) -6*a(n-20) -2*a(n-21) +2*a(n-22) -a(n-24) -a(n-25)

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A142511 A236070 A059705 * A015568 A322667 A101487

Adjacent sequences:  A218198 A218199 A218200 * A218202 A218203 A218204

KEYWORD

nonn

AUTHOR

R. H. Hardin Oct 23 2012

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 8 03:17 EST 2021. Contains 349590 sequences. (Running on oeis4.)