gip :=

    proc(i,j,pr) local c; c := iprod(pr[i],pr[j]); if c <= 0 then {i,j} fi end

                                    R := E7

                                      1281

                                      888

                               false, c, .873003

                              false, c, 811.225760

true,

   [{2, 9, 15, 20, 53, 56, 58}, {5, 12, 40, 43, 46, 59, 60},

       {4, 11, 28, 32, 50, 54, 61}, {3, 31, 36, 47, 51, 55, 62},

       {14, 27, 38, 42, 57, 63}, {7, 13, 25, 30, 41, 44}, {6, 18, 24, 35, 49},

       {19, 34, 39, 48, 52}, {1, 8, 21, 26}, {23, 29, 33}, {10, 17, 37},

       {16, 22, 45}],

   5.365560

1   1116.470
2   10269.530
3   12278.489
4   19523.659
5   24246.060
6   27258.979
7   30375.529
8   32319.569
9   33312.559
true,

   [{4, 11, 28, 32, 50, 54, 61}, {3, 10, 15, 37, 42, 47, 62},

       {1, 8, 14, 21, 27, 34, 63}, {9, 23, 35, 38, 53, 58},

       {16, 30, 45, 48, 56, 60}, {6, 12, 24, 29, 49, 55}, {7, 19, 31, 36, 51},

       {2, 20, 26, 33, 39}, {5, 17, 22, 40, 46}, {13, 25, 41, 44, 57},

       {18, 43, 52, 59}],

   23627.98306

> quit;
bytes used=290698028232, alloc=2948580, time=33351.10