561330

Appears in sequences

• Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1, 64*k-1 and 128*k-1 are all primes.at n=5A101320
• Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1 and 64*k-1 are all primes.at n=21A101994
• Numbers k for which 2*k-1, 4*k-1, 8*k-1, 16*k-1, 32*k-1, 64*k-1 and 128*k-1 are primes.at n=0A124514
• a(n) = least k such that 2^i*k-1 is prime for 1<=i<=n.at n=6A124516
• Numbers n such that 2n-1, 4n-1, 8n-1, 16n-1, 32n-1 and 64n-1 are primes.at n=6A125113
• Triangle read by rows: T(n,k) is number of hex trees with n edges and k leaves (n >= 1, 1 <= k <= 1 + floor(n/2)).at n=38A126177
• Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n having k DDU and LDU's.at n=40A128727
• Triangular array read by rows: row n shows the coefficients of the polynomial p(x,n) constructed as in Comments; these polynomials form a strong divisibility sequence.at n=40A328644