Numerator of (-1/3)^n*sqrt(Pi)/(Gamma(1/2 - n)*Gamma(1 + n)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =5a(4) =35a(5) =7a(6) =77a(7) =143a(8) =715a(9) =12155a(10) =46189a(11) =29393a(12) =676039a(13) =1300075a(14) =185725a(15) =1077205a(16) =33393355a(17) =21607465a(18) =756261275a(19) =1472719325a(20) =3829070245a(21) =22427411435a(22) =87670790155a(23) =19058867425a(24) =895766768975