165592domain: NAppears in sequencesa(n) = binomial(n,2) * !n.at n=8A061834Smallest number k such that k*n +/- 1, k*n^2 +/- 1, and k*n^3 +/- 1 are three sets of twin primes. a(n) = 0 if no such number exists.at n=8A239021G.f. satisfies A(x) = (1 + x)^2 + x*A(x)^3.at n=7A366696