A292757 - OEIS

%I #16 Sep 29 2023 12:01:45

%S 1,2,4,15,72,467,3534,31675,321832,3692927,46988914,658330035,

%T 10056866292,166476324887,2967375285294,56673879465595,

%U 1154538708267952,24990204586402847,572731801523141674,13855288923332516355,352821804274904668812,9433763230045116440807,264251645557758720762054

%N Expansion of e.g.f. exp(x)*(1+tan(x))/((1-tan(x))*(tan(x)+sec(x))).

%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^(2*n + 3) * n^(n + 1/2) / ((2 + sqrt(2)) * Pi^(n + 1/2) * exp(n - Pi/4)). - _Vaclav Kotesovec_, Jun 02 2019

%t nmax = 20; CoefficientList[Series[Exp[x]*(1+Tan[x])/((1-Tan[x])*(Tan[x]+Sec[x])), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Jun 02 2019 *)

%Y Cf. A000834.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Sep 26 2017