77781

Appears in sequences

• Numbers n such that 9*10^n + 8*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=20A103109
• Number of 3Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=10A207763
• Numbers n whose digits match the almost-natural numbers from A007376(n) onwards.at n=13A258785
• Number of nX4 0..1 arrays with every element unequal to 0, 2, 3, 6 or 7 king-move adjacent elements, with upper left element zero.at n=21A305043