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%I #16 Sep 29 2023 12:01:34
%S 1,3,9,30,117,528,2709,15600,99657,699648,5355009,44382720,396019197,
%T 3785146368,38583663309,417826928640,4790367838737,57967904882688,
%U 738337496799609,9873907221135360,138327377598038277,2025896274960580608,30959719452721035909,492827536493909114880
%N Expansion of e.g.f. (tan x + sec x)^3.
%H C. K. Cook, M. R. Bacon, and R. A. Hillman, <a href="https://www.fq.math.ca/Papers1/55-3/CookBaconHillman01222017.pdf">Higher-order Boustrophedon transforms for certain well-known sequences</a>, Fib. Q., 55(3) (2017), 201-208.
%F a(n) ~ 2^(n + 11/2) * n^(n + 5/2) / (Pi^(n + 5/2) * exp(n)). - _Vaclav Kotesovec_, Jun 02 2019
%t nmax = 20; CoefficientList[Series[(Tan[x]+Sec[x])^3, {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Jun 02 2019 *)
%Y Cf. A000111, A001250.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Sep 26 2017
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