a(n) = sum of remainders of n mod 2,4,6,...,2k, where k = [ n/2 ].

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =2a(5) =2a(6) =5a(7) =2a(8) =6a(9) =8a(10) =13a(11) =6a(12) =12a(13) =16a(14) =23a(15) =16a(16) =24a(17) =24a(18) =33a(19) =26a(20) =36a(21) =44a(22) =55a(23) =34a(24) =46a(25) =56a(26) =69a(27) =62a(28) =76a(29) =72