(1/5) times the sum of the elements of all subsets of [n] whose sum is divisible by five.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =4a(5) =12a(6) =29a(7) =71a(8) =186a(9) =468a(10) =1144a(11) =2718a(12) =6390a(13) =14920a(14) =34440a(15) =78720a(16) =178320a(17) =401088a(18) =896576a(19) =1992416a(20) =4404288a(21) =9689056a(22) =21223216a(23) =46305264a(24) =100663680a(25) =218104640a(26) =471104880a(27) =1014686160a(28) =2179696352a(29) =4670778048