use bignum qw/a 400/;$n=shift||10;$w+=1/($_/1)->bfac for 0..125;$w
="$w";sub P{$a=$_;($a%$_)||return for 2,3..sqrt;1}for$o(2..length(
$w)-$n){$_=substr $w,$o,$n;next if/^0/||!P;print"$_ \@ $o\n";last}