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A292758 E.g.f.: (tan x + sec x)^3. 2
1, 3, 9, 30, 117, 528, 2709, 15600, 99657, 699648, 5355009, 44382720, 396019197, 3785146368, 38583663309, 417826928640, 4790367838737, 57967904882688, 738337496799609, 9873907221135360, 138327377598038277, 2025896274960580608, 30959719452721035909, 492827536493909114880 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

C. K. Cook, M. R. Bacon, and R. A. Hillman, Higher-order Boustrophedon transforms ..., Fib. Q., 55 (No. 3, 2017), 201-208.

LINKS

Table of n, a(n) for n=0..23.

FORMULA

a(n) ~ 2^(n + 11/2) * n^(n + 5/2) / (Pi^(n + 5/2) * exp(n)). - Vaclav Kotesovec, Jun 02 2019

MATHEMATICA

nmax = 20; CoefficientList[Series[(Tan[x]+Sec[x])^3, {x, 0, nmax}], x] * Range[0, nmax]! (* Vaclav Kotesovec, Jun 02 2019 *)

CROSSREFS

Cf. A000111, A001250.

Sequence in context: A120018 A091353 A279199 * A297198 A297202 A003604

Adjacent sequences:  A292755 A292756 A292757 * A292759 A292760 A292761

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 26 2017

STATUS

approved

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Last modified November 28 03:29 EST 2021. Contains 349400 sequences. (Running on oeis4.)