Number of parts in all partitions of n in which no part occurs more than 3 times.

Terms

a(0) =1a(1) =3a(2) =6a(3) =8a(4) =15a(5) =24a(6) =36a(7) =50a(8) =75a(9) =102a(10) =143a(11) =197a(12) =264a(13) =349a(14) =467a(15) =606a(16) =789a(17) =1016a(18) =1299a(19) =1656a(20) =2100a(21) =2634a(22) =3302a(23) =4117a(24) =5106a(25) =6306a(26) =7772a(27) =9523a(28) =11639a(29) =14185