[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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