Representations by quaternary quadratic forms whose coefficients are 1, 4, 9 and 36

Explicit formulae are determined for the number of representations of a positive integer by the quadratic forms ax2+by2+cz2+dt2 with a,b,c,d∈{1,4,9,36}, gcd(a,b,c,d)=1 and a⩽b⩽c⩽d.