Apple's foray into the e-textbook business started off with a bang, according to a Monday report: The company sold more than 350,000 textbooks through its new version of iBooks in its first three days of availability, an analyst said.

Global Equities Research reported the sales in a note Monday morning, less than a week after Apple announced its education effort at the Guggenheim Museum in New York City on Thursday.

Apple's plan is embodied in three apps: A new version of Apple's iBooks lets students instantly access interactive digital textbooks through their mobile device. A second app called iBooks Author turns anyone with a basic knowledge of Apple tools into an iPad book publisher, offering layouts that can be jazzed up with interactive 3-D models, photos and videos. Then there's U, an app that lets teachers and students connect in various ways, including through posted reading lists and streamed video of lectures.

IBooks Author was downloaded 90,000 times in the first three days of availability, reported Global Equities Research, which tracks sales made through Apple's iBooks app, according to technology blog AllThingsD. All three applications are free.

High school e-textbooks available now are being sold for less than $15 in a partnership with three of the major U.S. .

The company's education initiative was the first major product launch since co-founder and former CEO died in October from pancreatic cancer.