[Issue 13371] std.math.factorial

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13371

--- Comment #8 from hsteoh at quickfur.ath.cx ---
auto factorial(T)(T t) {
        import std.range : drop, recurrence;
        return recurrence!"a[n-1] * n"(1).drop(t).front;
}


Happy now?

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