Find the smallest prime from a substring
Golfscipt, 33 32 bytes = -18 score
2{:x,2&gt;{x\%!},!!x`3$?)!|}{)}/;;x

Explanation:

2{...}{)}/ - starting with 2, while something is true, increment the top of the stack

;;x - discard the intermediate values collected by {}{}/ and the input, then put the last value tested there

:x,2&gt; - store the value as x, then produce a list from 2 to x-1

{x\%!},!! - keep those that x is divisible by, then coerce to boolean (not empty)

x`3?)! - look up the input in the text form of x (-1 if not found), increment, negate.

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