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PROJECT EULER · #0596

Number of Lattice Points in a Hyperball

Statement only · UnsolvedOriginal problem ↗

Let T(r) be the number of integer quadruplets x,y,z,t such that x2+y2+z2+t2r2. In other words, T(r) is the number of lattice points in the four-dimensional hyperball of radius r.

You are given that T(2)=89, T(5)=3121, T(100)=493490641 and T(104)=49348022079085897.

Find T(108)mod1000000007.

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