Path: news.eternal-september.org!eternal-september.org!feeder3.eternal-september.org!nntp-feed.chiark.greenend.org.uk!ewrotcd!.POSTED.chiark.greenend.org.uk!not-for-mail From: gtaylor@chiark.greenend.org.uk (Gareth Taylor) Newsgroups: rec.puzzles Subject: Re: Pythagorean Primitives Date: 26 Jun 2025 21:08:31 +0100 (BST) Organization: SGO Message-ID: References: <103352u$l35p$2@dont-email.me> Injection-Info: chiark.greenend.org.uk; posting-host="chiark.greenend.org.uk:93.93.131.173"; logging-data="26069"; mail-complaints-to="abuse@chiark.greenend.org.uk" X-Newsreader: trn 4.0-test77 (Sep 1, 2010) Originator: gtaylor@chiark.greenend.org.uk ([93.93.131.173]) In article , Charlie Roberts wrote: > Well, the goose may have finally been cooked (for me, at least). > > "The number of "primitive" triples for any side of a Pythagorean > triple is 2^(n-1), where n is the number of unique prime factors of > that side length. There may be more imprimitives than this but not > primitives." > > but no proof (or pointers to a proof) is given. Hello. Yesterday, I posted some maths waffle in a reply elsewhere in this thread. I mention it partly in case you missed it, but partly in case it hasn't shown up at all. (I haven't posted to a newsgroup for ages and might have got it wrong!) Gareth