login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A195950 Number of lower triangles of an n X n 0..3 array with no element greater than the number its nonzero horizontal and vertical neighbors 1
1, 5, 162, 17424, 6756437, 9790899054, 53438526965463, 1095434478598715742, 84189100478450762470628, 24264818647445156524051251366, 26234269948355443957604222160170467 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..16

EXAMPLE

Some solutions for n=4

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

..2.1......2.0......3.2......0.1......1.1......3.2......2.2......1.2

..1.2.0....3.3.2....1.3.0....2.1.2....3.2.2....2.1.1....1.1.1....1.1.1

..0.2.1.1..2.1.1.1..2.1.1.0..2.2.1.1..1.3.2.0..1.2.3.1..2.2.2.1..0.2.1.0

CROSSREFS

Sequence in context: A117068 A185832 A301667 * A195951 A128068 A197095

Adjacent sequences:  A195947 A195948 A195949 * A195951 A195952 A195953

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 25 2011

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 7 09:33 EST 2019. Contains 329843 sequences. (Running on oeis4.)