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A373771
Expansion of e.g.f. exp(x^2 / (2 * (1 - x)^3)) / (1 - x).
1
1, 1, 3, 18, 147, 1425, 15855, 200130, 2838465, 44767485, 777046095, 14705245170, 301014595035, 6621102973485, 155640761791515, 3891902825660850, 103115436832433025, 2884715829245475225, 84950805438277854075, 2626194012669689512050
OFFSET
0,3
FORMULA
a(n) = n! * Sum_{k=0..floor(n/2)} binomial(n+k,n-2*k)/(2^k * k!).
PROG
(PARI) a(n) = n!*sum(k=0, n\2, binomial(n+k, n-2*k)/(2^k*k!));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 18 2024
STATUS
approved