4-magic series constant.

Terms

a(0) =1a(1) =177a(2) =5111a(3) =60962a(4) =430729a(5) =2158099a(6) =8488095a(7) =27903044a(8) =79895265a(9) =205033333a(10) =481386807a(11) =1049954918a(12) =2152397897a(13) =4185095383a(14) =7774354687a(15) =13878462600a(16) =23923217921a(17) =39978597945a(18) =64985300791a(19) =103041066666a(20) =159757914953