One of the important math-poetry projects that I have been involved in is Strange Attractors: Poems of Love and Mathematics, a poetry anthology collected and edited by mathematician-poet Sarah Glaz and me -- published by AK Peters/CRC Press in 2008 and now available on Kindle and at various online used-book sites.
A poem in Strange Attractors that I have been drawn to again recently is "Ode to Numbers" by Chilean poet Pablo Neruda (1904-1973). Here are its opening lines:
from Ode to Numbers by Pablo Neruda
Oh, the thirst to know
how many!
The hunger
to know
how many
stars in the sky!