Hofstadter Figure-Figure sequences
These two sequences of positive integers are defined as:
$R(1)=1\ ;\ S(1)=2 \\R(n)=R(n-1)+S(n-1), \quad n>1.$
The sequence $S(n)$ is further defined as the sequence of positive integers not present in $R(n)$.
Sequence $R$ starts:
1, 3, 7, 12, 18, ...
Sequence $S$ starts:
2, 4, 5, 6, 8, ...
Test
{{test}}Console output