That's not a solution. I asked for a something that checks decimal numbers. A real solution looks uglier: check out https://github.com/matthiasgoergens/Div7, it starts

((((((6(2|9)8|6(2|9)1|5)(5(2|9)8|5(2|9)1|4)(5(2|9)7 [...]

(Unless you can convert from decimal to unary in regex, too. I doubt you can, regular languages are too weak for that.)