Expansion of 1/((1-x)(1-2x)(1-4x)(1-6x)).

Terms

a(0) =1a(1) =13a(2) =113a(3) =833a(4) =5649a(5) =36561a(6) =230161a(7) =1424401a(8) =8720657a(9) =53021969a(10) =320925969a(11) =1936736529a(12) =11665150225a(13) =70169841937a(14) =421734846737