Expansion of 1/((1-2x)(1-3x)(1-5x)(1-6x)).

Terms

a(0) =1a(1) =16a(2) =165a(3) =1400a(4) =10661a(5) =75936a(6) =517525a(7) =3421000a(8) =22124421a(9) =140796656a(10) =885205685a(11) =5513890200a(12) =34098207781a(13) =209668346176