Expansion of g.f.: (1+x^2)*(1+2*x^2)*(1+3*x^2)*(1+4*x^2)/(1-5*x+10*x^2 -40*x^3+35*x^4-105*x^5 +50*x^6-100*x^7+24*x^8-24*x^9).
A123894
Expansion of g.f.: (1+x^2)*(1+2*x^2)*(1+3*x^2)*(1+4*x^2)/(1-5*x+10*x^2 -40*x^3+35*x^4-105*x^5 +50*x^6-100*x^7+24*x^8-24*x^9).
Terms
- a(0) =1a(1) =5a(2) =25a(3) =115a(4) =525a(5) =2405a(6) =11025a(7) =50525a(8) =231525a(9) =1060979a(10) =4862065a(11) =22280875a(12) =102104045a(13) =467901065a(14) =2144199765a(15) =9825991725a(16) =45028504525a(17) =206347239279a(18) =945605099381
External references
- oeis: A123894