Musk’s Twitter bid appeared to include a recurring reference to marijuana.

When Elon Musk has been at the center of a media storm, there has been a common thread that has appeared several times.

In some form or fashion, the number 420 — which is often used to reference all things cannabis — has appeared in filings, tweets and interviews related to Mr. Musk and his business. On Thursday, when Mr. Musk’s offer to purchase Twitter became public, the share price he chose — $54.20 — caught people’s attention.

The price was reminiscent of Mr. Musk’s 2018 proposal to take Tesla private at $420 per share.

The Securities and Exchange Commission said that the funding Mr. Musk had alluded to was not so secure and that he had misled investors. In its 2018 complaint, the S.E.C. wrote that Mr. Musk said he had rounded up the share price to $420 from $419 “because he had recently learned about the number’s significance in marijuana culture.” The filing quoted Mr. Musk saying he believed his girlfriend “would find it funny, which admittedly is not a great reason to pick a price.”

Later in 2018, Mr. Musk smoked marijuana during an interview on the show “The Joe Rogan Experience,” which was widely shared and turned into memes. He poked fun at that discussion last week on Twitter, sharing one of those memes.