3 ms·
Many banks apparently don't let you choose PINs; however from the limited sample of PINs I know of (mine, my wife, my company and a few others) they're not rand
by wazoox 14y ago
Many banks apparently don't let you choose PINs; however from the limited sample of PINs I know of (mine, my wife, my company and a few others) they're not random; they all have doubled digits (like 2554).
- finnw 14y agoIt could be a coincidence. About half of all 4-digit numbers contain at least one repeated digit. (Of 10000 possible numbers, 10 * 9 * 8 * 7 == 5040 contain four distinct digits.)
- ralph 14y agoRight, and about a quarter contain the same digit at least twice in a row, which may be the "double digit" the grandparent referred to. $ pins() { seq -f '%04.0f' 0 9999; } $ pins | egrep -c '(.)\1' 2710 $ pins | egrep -c '(.).*\1' 4960 $
- ralph 14y agoFurther to my reply to sibling-reply finnw, here's the pattern of digits, further showing his 10 * 9, etc., breakdown. $ pins | > sed -r ' > :a; s/^([0-9])(.*)\1/\1\2a/; ta; s/[0-9]/a/ > :b; s/a([0-9])(.*)\1/a\1\2b/; tb; s/[0-9]/b/ > s/([0-9])\1/cc/; s/[0-9]/c/ > s/[0-9]/d/ > ' | > sort | uniq -c | sort -n 10 aaaa 90 aaab 90 aaba 90 aabb 90 abaa 90 abab 90 abba 90 abbb 720 aabc 720 abac 720 abbc 720 abca 720 abcb 720 abcc 5040 abcd $