Lenstra's Numbers

We have $1233={12}^2+{33}^2$

In homage to Hendrik Lenstra who first noticed this property let's call such integers Lenstra's numbers.

Find the first 36-digits Lenstra's number i.e. n such as :
$n=d_1{d}_2\dots d_{36}={d_1{d}_2\dots d_{18}}^2+{d_{19}{d}_{20}\dots d_{36}}^2$

[My timing: < 1 sec]