138138domain: NAppears in sequencesa(n) = n*(n+1)*(n+2)*(n+3)*(3*n+2)/120.at n=21A051836Numbers m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,19.at n=15A064246a(n) = (n+1)*(n+2)^2*(n+3)*(n+4)*(n+5)*(2*n+3)/720.at n=10A108681Expansion of (8+6*x)/(1-x)^5.at n=20A190048