OFFSET
1,3
COMMENTS
Bouwer and Star give a recurrence.
REFERENCES
Bouwer, I., and Z. Star. "A question of protocol." The American mathematical monthly 95.2 (1988): 118-121. See O(n).
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
PROG
(PARI) A360514seq(n) = {my(a=vector(n)); a[1]=a[2]=1; for(n=3, n, a[n] =(n-1) * if(n%2, 2*a[n-2], a[n-2] + (n-2)*a[n-3]) + 2*sum(k=1, (n-3)\2, binomial(n-1, 2*k) * k*(n-2*k-1)*a[2*k-1]*a[n-2*k-2])); a} \\ Andrew Howroyd, Feb 27 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 27 2023
EXTENSIONS
Terms a(11) and beyond from Andrew Howroyd, Feb 27 2023
STATUS
approved