A352608 a(n) = Bell(n)*n!!.

1, 1, 4, 15, 120, 780, 9744, 92085, 1589760, 19983915, 445344000, 7053735150, 194162549760, 3735730993995, 123152970608640, 2803291544678625, 108175188829962240, 2855475766145702700, 126726160086516695040, 3818865908630429932275, 192201344414226343526400

Offset: 0

Author

Peter Luschny, Mar 23 2022

Keywords

• nonn

Crossrefs

Cf. A000110, A006882, A081066.

Programs

Maple

seq(doublefactorial(n)*combinat:-bell(n), n=0..20);

Formula

a(n) = A000110(n)*A006882(n).