Primality proof for n = 1903129742795028023201:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=1249292843947.html>1249292843947 is prime.</a>
<br>b^((n-1)/1249292843947)-1 mod n = 926103283304007242421, which is a unit, inverse 1840810486281443399242.
<p>(1249292843947) divides n-1.
<p>(1249292843947)^2 > n.
<p>n is prime by Pocklington's theorem.