If anyone has an elegant way of deleting the cases where we have duplicate characters I would love to see it. My 2 line regex is functional, but fairly agricultural!

I won't claim elegance, but above I constructed character classes on the fly for that. Each partial solution like ($T,$H,$R,$E,$N) is used to form "[^$T$H$R$E$N]". That is applied to 3-digit candidates which are already filtered for unlike digits.

After Compline
Zaxo

Update: Rereading your statement, I saw I'd filtered that too :-) I used $_ !~ m/(\d)\d*\1/g to filter out matching digits.

In reply to Re: Re: (Efficiency Golf) Triangular numbers by Zaxo
in thread (Efficiency Golf) Triangular numbers by jepri

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