175824domain: NAppears in sequencesn = k^2 - (reversal of k)^2 for two different values of k.at n=17A087672a(1)=a(2)=1. For n >= 3, a(n) = (product{k=1 to n-1} a(k)) - (sum{j=1 to n-1} a(j)).at n=8A123702a(n) = sigma(A291789(n)).at n=20A291804Expansion of 1 / ( (1-3*x) * (1-6*x) )^(2/3).at n=7A383937