I think it's as easy as this: 
$_="abcedf 5163 1234 5678 or 1234516323943293";
print "$1\n" while /(5163(?:\s*\d){8})/g;

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In reply to Re: How to write a regular expression to extract a number from an embedded string? by Skeeve
in thread How to write a regular expression to extract a number from an embedded string? by jwking

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