login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

T(n,k)=Number of nXk 0..3 arrays with no three equal values forming an isosceles right triangle, and new values introduced in 0..3 order.
4

%I #4 Jun 05 2016 14:18:43

%S 1,2,2,5,10,5,15,105,105,15,51,1264,2766,1264,51,187,15418,49702,

%T 49702,15418,187,715,188465,784878,543906,784878,188465,715,2795,

%U 2304141,13322548,4010258,4010258,13322548,2304141,2795,11051,28171070,232027264

%N T(n,k)=Number of nXk 0..3 arrays with no three equal values forming an isosceles right triangle, and new values introduced in 0..3 order.

%C Table starts

%C .........1.................2...................5............15......51......187

%C .........2................10.................105..........1264...15418...188465

%C .........5...............105................2766.........49702..784878.13322548

%C ........15..............1264...............49702........543906.4010258.16365681

%C ........51.............15418..............784878.......4010258.5029904...725420

%C .......187............188465............13322548......16365681..725420.....2890

%C .......715...........2304141...........232027264......55643290...30060.......12

%C ......2795..........28171070..........4056338728.....210405148....1337........2

%C .....11051.........344428103.........70402715640.....904155053......54........0

%C .....43947........4211086174.......1221782263634....4384022592......11........0

%C ....175275.......51486063258......21228810396872...21350702064.......0........0

%C ....700075......629484802987.....368923543916728..105038486755.......0........0

%C ...2798251.....7696279187803....6410003754557834..514302715276.......0

%C ..11188907....94097130028610..111371494441358332.2558243582787

%C ..44747435..1150461107685501.1935130749075453956

%C .178973355.14065899352150196

%C .715860651

%H R. H. Hardin, <a href="/A273964/b273964.txt">Table of n, a(n) for n = 1..153</a>

%F Empirical for column k:

%F k=1: a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3)

%F k=2: [order 7] for n>8

%e Some solutions for n=3 k=4

%e ..0..0..1..2. .0..1..2..1. .0..1..2..1. .0..1..0..2. .0..0..1..0

%e ..3..3..2..1. .3..1..2..0. .0..1..3..2. .0..1..0..1. .2..2..1..3

%e ..1..2..3..1. .3..2..1..3. .3..2..1..0. .3..1..3..2. .3..3..2..1

%Y Column 1 is A007581(n-1).

%K nonn,tabl

%O 1,2

%A _R. H. Hardin_, Jun 05 2016