26847

Appears in sequences

• 1 - (5/6)*n + (5/2)*n^2 + (10/3)*n^3 + n^4.at n=12A057675
• Triangle T(n,k) = (2*n-k-1)*T(n-1,k-1) + (k+1)*T(n-1,k), with T(n,1) = T(n,n) = 1, 1 <= k <= n, read by rows.at n=24A156139
• Antiharmonic numbers using anti-divisors: numbers n such that sigma*(n) divides sigma*_2(n), where sigma*(n) is the sum of anti-divisors of n and sigma*_2(n) the sum of squares of anti-divisors of n.at n=15A192286
• Composite numbers whose multiplicative persistence is 6.at n=35A199996
• Number of edges formed by sides and straight "chords" in a right triangle when each side is divided by vertices into n equal segments.at n=9A274586
• Ulam numbers k such that k/3 is also an Ulam number.at n=38A287212
• a(n) is the smallest k which satisfies (j^2 + k)/(j + k^2) = n where j,k are integers and j >= k > 0.at n=65A290333