127469domain: NAppears in sequencesExpansion of g.f. (1-x^2)/(1-x-2*x^2+x^3).at n=21A028495Row sums of triangle A060556.at n=10A060557a(n) = numerator(Sum_{k=1..n} 1/(prime(k)-1)).at n=9A120271Number of palindromic compositions of n with parts in {1,2,4,6,8,10,...}.at n=43A276055