A255709 No three points (i,a(i)), (j,a(j)), (k,a(k)) are collinear and all values distinct, for n = 0,1,2,... the value of a(n) is chosen to be m or -m (in this order) for the smallest m>=0 satisfying the condition.

0, 1, -1, 2, 3, -2, -5, -3, 4, -6, 6, -7, -4, 5, 12, 16, 7, 8, -10, -8, 9, 19, 14, -12, -14, -9, 21, 10, -11, -15, 17, 15, -19, 13, -22, -13, -16, -24, 11, 18, 22, -18, 25, 23, -17, 24, 40, -21, -38, 20, -29, 36, -30, -20, 32, -34, 26, 43, -23, 37, -26, 33

Offset: 0

Author

Alois P. Heinz, Mar 03 2015

Keywords

• sign
• look

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..20000

Crossrefs

Cf. A005836, A179040, A231334, A236266, A236335, A255708.

Programs

Maple

b:= proc() true end:
a:= proc(n) option remember; local i, j, k, t, ok;
      for t from 0 do for k in [t, -t] do ok:=b(k);
        for j from n-1 to 1 by -1 while ok do
          for i from j-1 to 0 by -1 while ok do
            ok:= (n-j)*(a(j)-a(i))<>(j-i)*(k-a(j))
        od od; if ok then b(k):=false; return k fi
      od od
    end:
seq(a(n), n=0..60);