Sumukhaschaikadanthascha, Kapilo Gaja Karnika,
Lambhodarascha Vikato Vignarajo Vinayaka
Dhoomakethurganadhyaksha Phalachandro Gajanana,
Vakra Thunda Soorpakarno Herambha Skanda poorvaja
Shodasaithani namani ya padeth srunuyadhapi,
Vidhyarambhe vivahe cha pravese, nirgame thadha,
Sangrame sarvakarye cha vigna sthasya na jayathe
This stotra is about the 16 names of Lord Ganesha along with phala shruti. This stotra is supposed to be from the 24th Prakarana of Upasana Khanda of Ganesa Purana.
Source: http://www.celextel.org/stotras/ganesha/ganapatishodasastotram.html
In the above link it is given that the stotra is from Ganesha purana but it's not. There is a hint in the below document at page 21 that the stotra might be from Skanda purana
http://www.kamakoti.org/kamakoti/books/ESSENCE%20OF%20GANESHA%20MAHIMA.pdf
If anyone happens to know where exactly in Skanda purana the stotra is mentioned, kindly let me know.