2027510

Appears in sequences

• a(n) = n*a(n-2) + a(n-5) for n >= 5 and with a(0)=0, a(1)=1, a(2)=0, a(3)=3, a(4)=0.at n=15A130637
• Least k such that sigma(k*n)/tau(k*n) = sigma(k*n+1)/tau(k*n+1), or 0 if no such k exists.at n=47A274774