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G.f.: exp( Sum_{n>=1} A113184(n^2)*x^n/n ), where A113184(n) = difference between sum of odd divisors of n and sum of even divisors of n.
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%I #7 Apr 15 2013 21:24:42

%S 1,1,3,7,16,30,64,120,236,434,805,1445,2614,4568,8003,13783,23616,

%T 39886,67124,111652,184862,303282,495001,801939,1292968,2070628,

%U 3300796,5232112,8256081,12961543,20264168,31535316,48882592,75455902,116041910,177775284,271401683

%N G.f.: exp( Sum_{n>=1} A113184(n^2)*x^n/n ), where A113184(n) = difference between sum of odd divisors of n and sum of even divisors of n.

%C Compare to: exp(-Sum_{n>=1} A113184(n)*x^n/n ) = Sum_{n>=1} (-x)^(n*(n+1)/2).

%H Paul D. Hanna, <a href="/A224340/b224340.txt">Table of n, a(n) for n = 0..1000</a>

%F Logarithmic derivative yields A224339.

%e L.g.f.: A(x) = 1 + x + 3*x^2 + 7*x^3 + 16*x^4 + 30*x^5 + 64*x^6 + 120*x^7 +...

%e where

%e log(A(x)) = x + 5*x^2/2 + 13*x^3/3 + 29*x^4/4 + 31*x^5/5 + 65*x^6/6 + 57*x^7/7 + 125*x^8/8 + 121*x^9/9 +...+ A113184(n^2)*x^n/n +...

%o (PARI) {a(n)=polcoeff(exp(sum(k=1,n,sumdiv(k^2, d, (-1)^d*d)*(-x)^k/k)+x*O(x^n)),n)}

%o for(n=0,40,print1(a(n),", "))

%Y Cf. A224339, A113184.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Apr 03 2013