G.f.: Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(3*n-3), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
A355348
G.f.: Sum_{n=-oo..+oo} x^(n*(n+1)/2) * C(x)^(3*n-3), where C(x) = 1 + x*C(x)^2 is the g.f. of the Catalan numbers (A000108).
Terms
- a(0) =2a(1) =-7a(2) =0a(3) =26a(4) =-42a(5) =63a(6) =-111a(7) =90a(8) =54a(9) =-273a(10) =451a(11) =-396a(12) =275a(13) =-561a(14) =1287a(15) =-1781a(16) =1365a(17) =-351a(18) =-871a(19) =2938a(20) =-5733a(21) =7008a(22) =-5172a(23) =2331a(24) =-1905a(25) =5835a(26) =-14688a(27) =24752a(28) =-27455a(29) =19278
External references
- oeis: A355348