91839

Appears in sequences

• Numbers n such that 9*10^n + 8*R_n - 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=10A103108
• a(n) = [x^n] f(x)^n, where f(x) = (1 - x^7)^7/((1 - x^2)^2 * (1 - x^5)^5).at n=11A372212
• Indices of octagonal pyramidal numbers that are both octagonal and octagonal pyramidal.at n=5A378918