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A009008 Expansion of e.g.f.: 1/cos(sin(x)) (even-indexed coefficients only). 5
1, 1, 1, -23, -415, 849, 421089, 16027897, -602344127, -137830187103, -6375572516543, 1282077224074761, 294398207479497377, 6767832711454751473, -10535904130516747834591, -2468712006908963695579879, 172926818125145929773139073 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Vincenzo Librandi and Alois P. Heinz, Table of n, a(n) for n = 0..100 (first 51 terms from Vincenzo Librandi)

MATHEMATICA

f[x_] := Sec@Sin[x]; Table[Derivative[2*n][f][0], {n, 0, 16}] (* Arkadiusz Wesolowski, Aug 18 2012 *)

With[{nmax = 50}, CoefficientList[Series[1/(Cos[Sin[x]]), {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 21 2018 *)

PROG

(PARI) x='x+O('x^50); v=Vec(serlaplace(1/cos(sin(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 21 2018

CROSSREFS

Sequence in context: A245805 A016197 A199821 * A286787 A226847 A203147

Adjacent sequences:  A009005 A009006 A009007 * A009009 A009010 A009011

KEYWORD

sign

AUTHOR

R. H. Hardin, Simon Plouffe

EXTENSIONS

a(16) from Arkadiusz Wesolowski, Aug 18 2012

STATUS

approved

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Last modified October 17 03:15 EDT 2018. Contains 316275 sequences. (Running on oeis4.)