A283669 a(n) = q(n-q(n+1)+2) - q(n-q(n)+2) where q(n) = A005185(n).

0, -1, -1, 0, -1, -1, 0, 0, 0, 0, -2, 0, 0, -1, 0, -1, -1, 0, 0, 0, 0, 0, -2, 2, 0, 0, 0, 0, 0, -1, 1, 0, -1, 1, 2, 0, -1, 0, -1, -1, 0, 0, 0, 0, 0, 0, -4, 3, -2, -4, 2, 2, -2, 0, 0, -2, 0, 0, 0, 0, 0, -1, 3, 4, -3, 1, -1, 0, 3, 4, 2, 1, -2, -1, 2, -2, 1, -1, 0, 1, 1, 0, -2, 1, -1, -1, 0, 0, 0, 0

Offset: 1

Author

Altug Alkan, Mar 13 2017

Keywords

• sign

Links

• Altug Alkan, Scatterplot of A283669 for 10^6 terms

Crossrefs

Cf. A005185.

Programs

Mathematica

q[1] = q[2] = 1; q[n_] := q[n] = q[n - q[n - 1]] + q[n - q[n - 2]]; a[n_]:= q[n - q[n + 1] + 2] - q[n - q[n] + 2] ; Table[a[n], {n, 90}] (* Indranil Ghosh, Mar 13 2017 *)

PARI

a=vector(1001); a[1]=a[2]=1; for(n=3, #a, a[n]=a[n-a[n-1]]+a[n-a[n-2]]); va = vector(1000, n, a[n+2-a[n+1]]-a[n+2-a[n]])