[seqfan] Sequence from buggy polyomino counter

Allan Wechsler acwacw at gmail.com
Thu Dec 20 17:03:49 CET 2018

I was trying to sharpen my Haskell skills by writing a program to compute
A048664, the number of different polyominos including the origin cell,
where rotations, translations, and reflections are considered distinct.

I wrote the code, compiled it a couple of times to get the syntax errors
out, and then tried it out. It has a bug. Instead of 1, 4, 18, 76, 315, it
produces 1, 4, 24, 192, 1856.

My first impulse was: fix the darned bug! But then I thought: wait a
second, maybe OEIS can help me find the bug. So I searched for the programs
buggy output sequence.

It's not in OEIS. Question: how much effort should I put into analyzing the
program's actual behavior? It might be doing something interesting that is
worth including. If anybody wants to try guessing, what's the next element?

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