A341900 Partial sums of A005165.

0, 1, 2, 7, 26, 127, 746, 5167, 41066, 368047, 3669866, 40284847, 482671466, 6267305647, 87660962666, 1313941673647, 21010450850666, 357001369769647, 6423384156578666, 122002101778601647, 2439325392333218666, 51212944273488041647, 1126440053169940898666

Offset: 0

Author

R. J. Mathar, Jun 04 2021

Keywords

• nonn
• easy

Crossrefs

Cf. A000142, A005165, A136580, A215096.

Formula

a(n)-a(n-1) = A005165(n).

a(n) = Sum_{i=0..floor((n-1)/2)} (n-2*i)!.

a(n) = A136580(n) - A059841(n).

D-finite with recurrence a(n) -n*a(n-1) -a(n-2) +n*a(n-3)=0.

a(n) = n! + a(n-2) for n >= 2. - Alois P. Heinz, Jun 04 2021