A099556 a(n) = Sum_{k=0..2*n} (n - floor(k/2))^k.

1, 2, 5, 18, 91, 604, 5123, 53808, 679389, 10107934, 174544505, 3451802006, 77302457079, 1942469215432, 54339334903015, 1680597906265988, 57116435383949097, 2121725700531106842, 85740960774906267853, 3753239245360442525498, 177284859933198522968819, 9004760569281510790598100

Offset: 1

Author

Paul D. Hanna, Oct 22 2004

Keywords

• nonn
• easy

Crossrefs

Cf. A099555.

Programs

PARI

a(n)=sum(k=0,2*n,(n-k\2)^k)

Formula

Row sums of triangle A099555.

Extensions

a(13) and following terms from Georg Fischer, Nov 21 2024