a(n) = Sum_{k=1..n} floor(n/(2*k-1))^k.

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =7a(5) =11a(6) =13a(7) =14a(8) =21a(9) =29a(10) =31a(11) =39a(12) =41a(13) =57a(14) =87a(15) =88a(16) =90a(17) =133a(18) =135a(19) =173a(20) =253a(21) =317a(22) =319a(23) =335a(24) =398a(25) =526a(26) =756a(27) =932a(28) =934a(29) =1300