A283655 a(n) = b(b(n+1)) - b(n-b(n)+1) where b(n) = A004001(n).

0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 4, 4, 4, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 6, 6, 6, 6, 7, 7, 7, 7, 7

Offset: 1

Author

Altug Alkan, Mar 13 2017

Keywords

• nonn

Examples

			a(1) = 0 since a(1) = A004001(A004001(2)) - A004001(1-A004001(1)+1) = 1 - 1 = 0.
		

Links

• Altug Alkan, Table of n, a(n) for n = 1..10000
• Altug Alkan, Illustration of A283655

Crossrefs

Cf. A004001, A004074, A233270, A249071.

Programs

Mathematica

b[1] = 1; b[2] = 1; b[n_] := b[n] = b[b[n - 1]] + b[n - b[n - 1]]; a[n_] := b[b[n + 1]] - b[n - b[n] + 1]; Array[a, 100] (* Robert G. Wilson v, Mar 13 2017 *)

PARI

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