Least positive integer whose multiset of prime indices has exactly n distinct semi-sums.

Terms

a(0) =1a(1) =4a(2) =12a(3) =30a(4) =60a(5) =210a(6) =330a(7) =660a(8) =2730a(9) =3570a(10) =6270a(11) =12540a(12) =53130a(13) =79170a(14) =110670a(15) =221340a(16) =514140a(17) =1799490a(18) =2284590a(19) =4196010a(20) =6750870a(21) =13501740a(22) =37532220a(23) =97350330a(24) =131362770a(25) =189620970a(26) =379241940a(27) =735844830a(28) =1471689660