G.f. satisfies A(x) = exp( Sum_{k>=1} ((-3)^k + A(x^k)) * x^k/k ).

Terms

a(0) =1a(1) =-2a(2) =5a(3) =-11a(4) =27a(5) =-70a(6) =188a(7) =-502a(8) =1355a(9) =-3712a(10) =10269a(11) =-28546a(12) =79777a(13) =-224153a(14) =632581a(15) =-1791644a(16) =5091109a(17) =-14510079a(18) =41464784a(19) =-118773034a(20) =340950420a(21) =-980660721a(22) =2825700987a(23) =-8155455450a(24) =23573749136a(25) =-68236663474a(26) =197774787066a(27) =-573915774310