a(n) = A142590(n)/3.

Terms

a(0) =0a(1) =7a(2) =5a(3) =39a(4) =4a(5) =95a(6) =33a(7) =175a(8) =14a(9) =279a(10) =85a(11) =407a(12) =30a(13) =559a(14) =161a(15) =735a(16) =52a(17) =935a(18) =261a(19) =1159a(20) =80a(21) =1407a(22) =385a(23) =1679a(24) =114a(25) =1975a(26) =533a(27) =2295a(28) =154a(29) =2639