508
SUPPLEMENTARY RESEARCHES ON THE PARTITION OF NUMBERS.
[154
The actual development, when k is small (for instance k = 1 or k = 2), is most readily
obtained by developing each factor separately and taking the product. To do this we
have
c j. , c + ° 2 i ¿o c + 4c 2 + c 3 , ^ , 0
t + 77 ^ ii 2 77 — it 3 + &C.,
1-ce-t 1 — c (l-c) 2 " ' (1 — c) 3 2
(l-c) 4
where by a general theorem for the expansion of any function of e*, the coefficient
of is
(-y 1
11/ l-c(l + A)
0/
(-)// 1
+
+
of
11/ U - c ' (1 - Gf ‘ (1 - c'y +1
(where as usual AO^ = 1/ — Of, A 2 0^ = 2f — 2 . V + Of, &c.) and
Of
1 - er* t + 2 + 12 t 720 f + 30240 &C ”
where, except the constant term, the series contains odd powers only and the coef
ficient of ¿ 2/_1 is — > Bi> B-2, B 3 ... denoting the series ~
YY ¿¿J o oU
numbers.
of Bernoulli’s
But when k is larger, it is convenient to obtain the development of the fraction
from that of the logarithm, the logarithm of the fraction being equal to the sum of
the logarithms of the simple factors, and these being found by means of the formulae
c c
t +
c + c 2 t 3 c + 4c 2 + c 3 t 2 0
X + —77 XT XT + &C.
1 — c (1 — c) 2 2 (l-c) 3 6^ (1-c) 4 24
l0g 1 - l0g t + 2 1 24 t2 + 2880 * 181440 V ' + &C ‘
The fraction is thus expressed in the form
1
gky-ykytz-y... •
11 (1 — p n ) II (ap) t k
and by developing the exponential we obtain, as before, the series commencing with
. 1
A -*w
Kesuming now the formula
XP = P A -*>
which gives %p as a function of p, we have
0x = u XP .
[1 — x a ] p — x ’