Q1: 73939133

matlab:
plist = 1:10;
plistn = 1:10;
for i = 1:20
plist = plistn;
plist = plist(isprime(plist));
plist = plist *10;

for j = 0:length(plist)-1
    for k = 0:9
        plistn(j*10+k+1) = plist(j+1)+k;
   
    end
end

end
max(plist/10)
isprime(max(plist)/10)