42470

Appears in sequences

• Numbers n such that 5*10^n + 7*R_n - 6 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=17A103019
• G.f.: A(x) = F(x*G(x)^2)^3 where F(x) = G(x*F(x)) = 1 + x*F(x)^3 is the g.f. of A001764 and G(x) = F(x/G(x)) = 1 + x*G(x)^2 is the g.f. of A000108 (Catalan).at n=6A153394
• Number of n X n 0..2 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 3.at n=8A240033
• a(n) = Product_{d|n} prime(d).at n=32A275700
• a(n) = 5*(n+1)*(9*n+4).at n=30A304507