Question Number 135373 by Bird last updated on 12/Mar/21
$${determine}\:{the}\:{sequence}\:{u}_{{n}} \\ $$$${wich}\:{verify}\:{u}_{{n}} \:+{u}_{{n}+\mathrm{1}} =\frac{\left(−\mathrm{1}\right)^{{n}} }{{n}!} \\ $$
determine-the-sequence-u-n-wich-verify-u-n-u-n-1-1-n-n-