A273961 Number of nX2 0..3 arrays with no three equal values forming an isosceles right triangle, and new values introduced in 0..3 order.
2, 10, 105, 1264, 15418, 188465, 2304141, 28171070, 344428103, 4211086174, 51486063258, 629484802987, 7696279187803, 94097130028610, 1150461107685501, 14065899352150196, 171974109566120666, 2102609553831755149
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1. .0..1. .0..1. .0..1. .0..1. .0..0. .0..0. .0..1. .0..1. .0..1 ..0..1. .1..0. .2..2. .2..1. .2..1. .1..2. .1..1. .1..2. .0..2. .1..2 ..2..3. .2..0. .3..1. .1..3. .2..3. .1..2. .0..2. .1..0. .0..3. .1..2 ..0..2. .1..1. .2..3. .0..2. .0..2. .1..0. .0..1. .2..1. .3..0. .0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..46
Crossrefs
Cf. A273964.
Formula
Empirical: a(n) = 14*a(n-1) -18*a(n-2) -54*a(n-3) +112*a(n-4) -30*a(n-5) -41*a(n-6) +18*a(n-7) for n>8
Empirical g.f.: 2*x -x^2*(10-35*x-26*x^2+152*x^3-85*x^4-49*x^5+30*x^6) / ( (x-1) *(x^2+x-1) *(18*x^4-41*x^3+6*x^2+12*x-1) ). - R. J. Mathar, Jun 06 2016
Comments