946121domain: NAppears in sequencesNumber of compositions of 7*n into parts 5 and 7.at n=19A373911a(n) = Sum_{k=0..floor(2*n/5)} binomial(2*k+1,2*n-5*k).at n=32A392455Expansion of 1 / ((1-x)^5 - x^7).at n=21A392546