1972819

Appears in sequences

• Add 1, multiply by 1, add 2, multiply by 2, etc.; start with 0.at n=19A019461
• a(0) = 1; a(n) = (n-1)*a(n-1) + n.at n=10A111063
• a(n) = numerator(Sum_{k=1..n} k^2/k!).at n=10A371831