53066

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 18.at n=22A031606
• a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 2.at n=16A049937
• Number of positive integers <= 10^n that are divisible by no prime exceeding 5.at n=31A106598
• Numbers n such that the multiplicative group of integers modulo n is isomorphic to C_m X C_m, m > 1.at n=12A305236
• a(n) = n*(2^(n-1) - n - 1).at n=10A342482