A283672 a(n) = gcd(q(n - q(n+1) + 2), q(n - q(n) + 2)) where q(n) = A005185(n).

1, 1, 1, 2, 1, 1, 3, 3, 3, 4, 1, 4, 5, 1, 5, 1, 1, 6, 6, 6, 6, 8, 2, 2, 8, 8, 8, 8, 10, 1, 1, 10, 1, 1, 1, 11, 1, 11, 1, 1, 12, 12, 12, 12, 12, 16, 2, 1, 2, 4, 2, 2, 2, 14, 16, 2, 16, 16, 16, 16, 20, 1, 1, 1, 1, 1, 1, 20, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 22, 1, 1, 23, 1, 1, 1, 1, 23, 24

Offset: 1

Author

Altug Alkan, Mar 14 2017

Keywords

• nonn

Examples

			a(4) = gcd(A005185(4 - A005185(5) + 2), A005185(4 - A005185(4) + 2)) = gcd(A005185(3), A005185(3)) = gcd(2, 2) = 2.
		

Links

• Altug Alkan, Table of n, a(n) for n = 1..10000
• Altug Alkan, Alternative scatterplot of A283672

Crossrefs

Cf. A005185, A283673.

Programs

Mathematica

q[1] = q[2] = 1; q[n_] := q[n] = q[n - q[n - 1]] + q[n - q[n - 2]]; Table[GCD[q[n - q[n + 1] + 2], q[n - q[n] + 2]], {n, 88}] (* Indranil Ghosh, Mar 14 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, gcd(a[n+2-a[n+1]], a[n+2-a[n]]))