Expansion of g.f. (1 + 7*x)/(1 - 50*x^2).

Terms

a(0) =1a(1) =7a(2) =50a(3) =350a(4) =2500a(5) =17500a(6) =125000a(7) =875000a(8) =6250000a(9) =43750000a(10) =312500000a(11) =2187500000a(12) =15625000000a(13) =109375000000a(14) =781250000000