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A009244 Expansion of e.g.f.: exp(tan(x))/cos(x). 3

%I

%S 1,1,2,6,20,92,448,2688,17296,127312,1013600,8850336,83547584,

%T 845380928,9196867072,105911556096,1301697829120,16814357324032,

%U 230093807905280,3294279618252288,49636887216382976

%N Expansion of e.g.f.: exp(tan(x))/cos(x).

%H Vaclav Kotesovec, <a href="/A009244/b009244.txt">Table of n, a(n) for n = 0..477</a>

%H P. Barry, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL17/Barry2/barry281.html">Constructing Exponential Riordan Arrays from Their A and Z Sequences</a>, Journal of Integer Sequences, 17 (2014), #14.2.6.

%t With[{nn=30},CoefficientList[Series[Exp[Tan[x]]/Cos[x],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Jun 06 2014 *)

%K nonn,easy

%O 0,3

%A _R. H. Hardin_

%E Extended and signs tested by _Olivier GĂ©rard_, Mar 15 1997

%E Prior Mathematica program replaced and definition clarified by _Harvey P. Dale_, Jun 06 2014

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Last modified September 26 05:00 EDT 2022. Contains 356986 sequences. (Running on oeis4.)