|
%I #2 Mar 30 2012 18:37:07
%S 1,-1,3,-21,319,-10193,674047,-91369921,25234490623,-14140806673665,
%T 16031563354478591,-36691986271455923201,169262051631703928107007,
%U -1571807846118598776606101505,29353752424684301883376834576383,-1101562988034649825668233119938625537
%N G.f. A(x) satisfies: 1 = Sum_{n>=0} A(x)^(n+1)*x^n/2^(n*(n-1)/2) where A(x) = Sum_{n>=0} a(n)*x^n/2^(n*(n-1)/2).
%F G.f.: A(x) = (1/x)*series_reversion[x*Sum_{n>=0} x^n/2^(n*(n-1)/2)].
%e A(x) = 1 - x + 3/2*x^2 - 21/8*x^3 + 319/64*x^4 - 10193/1024*x^5 +...
%e 1 = A(x) + A(x)^2*x + A(x)^3*x^2/2 + A(x)^4*x^3/8 + A(x)^5*x^4/64 + ...
%o (PARI) {a(n)=2^(n*(n+1)/2)*polcoeff((1/x)*serreverse(sum(k=1,n+1,x^k/2^(k*(k-1)/2))+O(x^(n+2))),n)}
%Y Cf. A118410.
%K sign
%O 0,3
%A _Paul D. Hanna_, Nov 23 2007
| 