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A009072
Expansion of e.g.f. cos(tan(x))/cos(x), even-indexed terms only.
1
1, 0, -8, -216, -7552, -349568, -20281216, -1350879232, -84211707904, 286327484416, 2529465981566976, 1100934401707376640, 421697958276604264448, 165461414536859529248768, 69271409331127446269067264
OFFSET
0,3
LINKS
MATHEMATICA
With[{nmax = 60}, CoefficientList[Series[Cos[Tan[x]]/Cos[x], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 24 2018 *)
PROG
(PARI) x='x+O('x^50); v=Vec(serlaplace(cos(tan(x))/cos(x))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018
CROSSREFS
Sequence in context: A123057 A353933 A362073 * A002897 A024289 A009106
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved