a(n) = a(n-1) + c(n) for n >= 3, a( ) increasing, given a(1)=2, a(2)=3; where c( ) is complement of a( ).

A022951

a(n) = a(n-1) + c(n) for n >= 3, a( ) increasing, given a(1)=2, a(2)=3; where c( ) is complement of a( ).