3705927297

Appears in sequences

• a(n) = Sum_{i=0..n} (n!/(n-i)!)^2.at n=8A006040
• a(2n-1) = n*a(2n-2), a(2n) = n*a(2n-1) + 1.at n=15A007876
• Interleaving A006040 and A228229.at n=15A375231