[seqfan] Can't log in + comments on A176479
Nikos Apostolakis
nikos.ap at gmail.com
Sat Dec 31 18:30:22 CET 2016
Dear all,
for some reason I'm unable to login. I've reset my password and all but
every time I try to log in I get the message: "An unexpected error happened
while authenticating. Sorry."
Anyway, the reason I wanted to log in was to edit the sequence A176479. I
want to add a comment:
"a(n) is also the number of bidegree sequences that are realizable by
directed trees with n edges."
I wanted also to add the formula "a(n) = sum_k=1^n
binomial(n-1,k-1)*binomial(n+k,n)".
I have also a correction: In the formula section, it says: "G.f.: 1/4 -
(x-3)/(4*sqrt(x^2-6*x+1))" this is actually an exponential generating
function.
Thanks for any help,
Nikos
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