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A013008 sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8... 0
1, -4, 80, -4384, 451328, -74726784, 18162914304, -6087614197760, 2690808196562944, -1516485688823611392, 1061352718471077658624, -903110171035290053246976, 918161695966849718656434176 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
Table of n, a(n) for n=0..12.
CROSSREFS
Sequence in context: A012042 A013139 A013007 * A013180 A322751 A000316
Adjacent sequences: A013005 A013006 A013007 * A013009 A013010 A013011
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved

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Last modified May 17 10:20 EDT 2024. Contains 372594 sequences. (Running on oeis4.)