BlankSequence
__ (two _ characters) or BlankSequence[]
is a pattern object that can stand for any sequence of one or more Wolfram Language expressions.
__h or BlankSequence[h]
can stand for any sequence of one or more expressions, all of which have head h.
Examples
Wolfram Research (1988), BlankSequence, Wolfram Language function, https://reference.wolfram.com/language/ref/BlankSequence.html.
Text
Wolfram Research (1988), BlankSequence, Wolfram Language function, https://reference.wolfram.com/language/ref/BlankSequence.html.
CMS
Wolfram Language. 1988. "BlankSequence." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/BlankSequence.html.
APA
Wolfram Language. (1988). BlankSequence. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BlankSequence.html