I have written a program to solve the lego counting problem - to count the number of different contiguous geometric structures that can be made from n identical 4 x 2 lego bricks, all connected orthogonally. the problem is solved for n up to 10 by Soren Eilers and others, see here.
My problem gives approximately the same answers as on that link, and match exactly for 1 and 2 bricks - giving 1 and 24 possibilities respectively.
But I get 1550 possibilities for 3 bricks whereas Eilers and others get 1560 bricks. For greater n they diverge further, but not massively. I have looked over my code and fixed a number of problems but cannot see any remaining errors. The only way I can see to fix the errors is to get a list of the 1560 n=3 configurations and compare it to the list of configurations my program generates.
For larger n it's not practical to generate a list of configs, because the number is so large. For instance n=6 gives 915m+ possibilities. But printing the approx 1.5k possibilities for n=3 is easy.
Does anybody know where I could find either a list of the configs, or a program that does the counting, which I could adapt to print out all configs found, then compare the list to my own?
I thought this question could go in the maths SE, on stack overflow, or on the "bricks" SE (for lego enthusiasts). I took a guess this might be the best one. IIRC SE discourages cross-posting.