Mini-challenge: First Prime of form 403333...

[Jim Horn]

Well, my WP 34S quickly ran through the 19 digit value before overflowing. My '50g is at home and I'm at work.

What's left? I've got Mathematica 10 on my Surface Pro 3 in my work bag. Lessee:

x=403;
d=3;
While[
!PrimeQ[x],
x=10x+3;
d++
];
Print[d];
Print[x];

That ran in under a second with 'd' being sizeable (and the printout of 'x' being more so). I won't spoil the fun with the actual values, though.

Thank you, Joe! How you done it?

(Unrelated note: Bob Hoover, RIP)