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A013007
sec(arctan(x)+tan(x))=1+4/2!*x^2+80/4!*x^4+4384/6!*x^6+436992/8!*x^8...
0
1, 4, 80, 4384, 436992, 70425984, 16592126976, 5395435991040, 2312302178205696, 1263775007737085952, 857643638399523454976, 707659940568946007474176, 697634806106676807565574144
OFFSET
0,2
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Sec[ArcTan[x]+Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Aug 26 2016 *)
CROSSREFS
Sequence in context: A013090 A012042 A013139 * A013008 A013180 A322751
KEYWORD
nonn
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved