Math::N...lePrimes(3)

💖 NAME 💖

Math::NumSeq::DeletablePrimes — bestie, these are the deletable primes, aka primes where you can yeet a digit and still be left with a prime that is also deletable. It's giving recursive slay. 🦋

Oh and btw, the manual name is Math::N...lePrimes(3), filed under User Contributed Perl Documentation, iykyk.

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✨ SYNOPSIS ✨

use Math::NumSeq::DeletablePrimes;
my $seq = Math::NumSeq::DeletablePrimes->new;
my ($i, $value) = $seq->next;

That's literally it. Three lines. Main character energy. 👑

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🌸 DESCRIPTION 🌸

Okay so. The deletable primes are primes where you can remove a digit and get another prime — and that prime has to be deletable too. It's primes all the way down, no cap. 💅

2, 3, 5, 7, 13, 17, 23, 29, 31, 37, 43, ...     (A080608)
starting i=0

Take 367 for example — it's a deletable prime because you can delete the 6 and get prime 37, and then from 37 you delete the 3 and get prime 7. Chain complete, gorgeous, iconic. 🎀

And like, there can be more than one chain of deleted digits, which is so extra of it. Same 367? Instead delete the 3 and you get 67, then on to 7. Two paths, both valid, we love a flexible queen.

Since every chain bottoms out at a single-digit prime — that's 2, 3, 5 or 7 — literally every value has at least one such digit in its ancestry. Periodt.

Leading zeros are not allowed, bestie. So the high digit cannot be deleted if it's followed by a zero. Example: 2003 is not a deletable prime. Deleting the 2 gives 003 and that's not allowed (even though it would be a prime, sad), and the other deletes to 203 or 200? Not primes. Sorry girl. 😭

🔢 Radix

Optional parameter radix picks a base other than decimal, for when you're feeling spicy. For binary radix=>2, the primes 2 and 3 — which are two bits, "10" and "11" — get reckoned as endpoints, in the manner of OEIS A096246, since there are no one-bit primes. So they're the floor of the whole thing. 🫶

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🧚 FUNCTIONS 🧚

See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence classes. The shared lore, if you will.

• $seq = Math::NumSeq::DeletablePrimes->new ()
• $seq = Math::NumSeq::DeletablePrimes->new (radix => $integer)

Create and return a new sequence object. Fresh out of the box, ready to serve. ✨

• $bool = $seq->pred($value)

Return true if $value is a deletable prime, in the selected radix. Vibe check: passed or not.

Real talk though — in the current code there's a hard limit of 2**32 placed on the $value to be checked, in the interests of not going into a near-infinite loop. So don't come at it with a gigantic number, it will simply not. 💀

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👀 SEE ALSO 👀

• Math::NumSeq
• Math::NumSeq::Primes
• Math::NumSeq::SophieGermainPrimes

Go read those too, they're all part of the same friend group. 🌈

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This whole page came to you courtesy of perl v5.42.0, dated 2025-07-25, under the name Math::N...lePrimes(3). Bye bestie, go delete some digits responsibly! 💜🌸🎀