In the OEIS sequence A049210, I noticed an odd notation I haven't seen before:
a(n) = (8*n-1)(!^8), n >= 1, a(0) = 1.
What does the
(!^8) mean? My first thought was something to do with factorials, but, to my knowledge, the factorial symbol must always be preceded by a number, like
(5+n)!. I have no idea what a
! would mean just floating around on its own.
I'm pretty sure it doesn't mean "take the factorial of
(8*n-1) and raise that value to the 8th power," since that would result in the numbers growing far faster than the sequence should.
In logic and computer science,
! is often used to mean "not," such that
true, but I don't think that would have any application here.