84221

Properties

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 52.at n=4A031640
• Define f(n,k) = floor[n/k] and a(n) = right concatenation of f(n,k) for k = 1 to int[(n+1)/2] or until one arrives at a 1.at n=7A068671
• Primes in A068671.at n=4A068672
• Lesser of two Pythagorean primes for which the Pythagorean triangles have the same area.at n=35A157184
• Number of n X 5 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally.at n=12A183337
• Primes whose position in the Wythoff array is immediately followed by a prime both in the next column and the next row.at n=34A352537
• Lesser of twin self primes, i.e., smaller member of the pair of self primes differing by 2.at n=10A380713
• Prime numbersat n=8210