The longrunning German science fiction series Perry Rhodan recently ran a contest whose winner, a certain Martin Felten, was included in issue number 2638 as a space actuary and inventor of a fivedimensional number system. (See here for an article in German containing more details about the reallife Felten.)
Hauke Reddmann, a frequent contributor to this site, writes:
Contributed by
Hauke Reddmann
The necessity of an insurance mathematician in space was
VERY well adapted to the titanic background of the series
(although you have to be a longtime Rhodan reader like me
to judge that). As you can guess with pulp, he's just a lousy
civilian, but in the face of Dastardly Deadly Danger [tm],
like all Terranians he outdoes himself. :)

Hauke also provides this translation of the passage involving the new number system:
(quoted from Perry Rhodan 2638: Zielpunkt MorpheusSystem)
Item: Number Sets
If we shortly come to the kinds of numbers: There are seven overall.
The further mankind developed, the futher math developed and with it
the numbers man learnt to handle.
First there were the naturals (N) to add and multiply. By subtraction
the whole numbers came to be, the division led to define the
rationals (Q). After that followed the reals (R) which already
allowed to do powers and draw roots. But since they don't allow to
draw roots from a negative number, there came the complex numbers
(C).
In the sense of algebraic operations the number kingdom was complete
 until ingenious heads arrived, defining for fourdimensional algebra
the set of hypercomplex numbers.
To solve the riddle of the lightning wave of the Quolnean Keretzes,
I had to use fivedimensional math, thus quintadim numbers.
From: Personal Notes, M. Felten

Hauke comments "Of course,
when it comes to dimensions, the whole thing degenerates
into mathbabble (math version of technobabble), the author
rather abuses the word and evidently never read John Baez :)"
By the last remark, I suppose he is referring to the fact that the reals, complex number, quaternions and octonians are the only number systems in that all division algebras have dimensions 1, 2, 4, and 8 as real vector spaces (as Baez shows here). So, one would not expect to see "quintadim numbers". However, it really depends on what one means by "number", and Herren is certainly correct that this notion has evolved over time. In particular, there are most definitely fivedimensional algebras that are studied by mathematicians and physicists, as one can see by looking here.
I wrote back to Hauke, asking for more details regarding the uses of statistics and mathematics in the book. He replied:
Contributed by
Hauke Reddmann
"Perry Rhodan" can't deny its beginnings in cold war
time (1960), and it began straight imperialist (some
say fascist, but that's way too harsh). Time went by,
ice cold warriors were replaced by hippie authors,
and the Terrans now prefer to have a trade imperium.
Still, around each corner a new invasor is lurking,
High Powers frell around with the laws of the universe,
and you can imagine that flying a trader space craft is a
rather dangerous biz.
One of the old "Immortals" (they don't age  a blaster
would quickly end their status :) from very old times
(me olde geezer was born in the same year PR started)
is Homer G. Adams, who is a "mutant" with the ability
to be a financial genius. So, ideally suited for
interstellar trading, but he still needs an assistent
for the insurance aspect (what's the probability this
poor space ship will be eaten by a black hole?).
And here Mr. Felten fit in perfectly.
Unluckily for you and me, this was only background,
and not that much elaborated. (Still, he gets rather
many of these diary entries, where you can read about
his life  or rather of the real life Martin Felten.)
In the actual plot, he uses his 5D mathbabble to find
some plotdrivium that helps against the weapon of the
Quolnean Keretzes (you know you are a Rhodan fan when
you can type this without thinking :) mentioned in
the snip. Unluckily for him, he has to test his theory
under field conditions, read, a wrecked Keretze space
ship which is going to explode under his civilian butt
due to the laws of plot :)
So, no larger descriptions of the everyday life of an
actuary, but maybe author Marc A. Herren shied away
from the additional research. After all, Perry Rhodan
is light fiction. :)

