41671597domain: NAppears in sequencesG.f.: (1+x^2)/((1-2x)(1-x-x^2)); a(n)=3a(n-1)-a(n-2)-2a(n-3); a(n)=5*2^n-L(n+3); a(n)=sum{k=0..n, (L(k)-0^k)2^(n-k)}.at n=23A099166