For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Giohk404:branches:science/openSUSE_Tumbleweed/home:Giohk404:branches:science.repo
zypper refresh
zypper install octave
For openSUSE Factory PowerPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Giohk404:branches:science/openSUSE_Factory_PowerPC/home:Giohk404:branches:science.repo
zypper refresh
zypper install octave
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Giohk404:branches:science/16.0/home:Giohk404:branches:science.repo
zypper refresh
zypper install octave