[cortesi]

I once correctly guessed a that friend's PIN was "1729", based only on the fact that he was a maths major, a huge fan of Ramanujan, and was sure to have read this story. I still cherish the look of complete confusion on his face, more than 20 years later.

[samb1729]

Reading this comment makes me glad I use a different (but still nerdy) pin :)

[somethingsright]

Is it in here? 4242 9801 1089 1024 3141 1415 2718 1412 1732 1428 2997 6626 6022

[Scarblac]

1337?

[vba616]

One approach to PINs is to take two numbers that are familiar, but aren't related to each other and interleave them.

Basically the same principle as correct horse battery staple.