a(n) = Sum_{k<=n} A007955(k) * A007955(n-k+1), where A007955(m) = product of divisors of m.

Terms

a(0) =1a(1) =4a(2) =10a(3) =28a(4) =51a(5) =140a(6) =252a(7) =452a(8) =953a(9) =1164a(10) =2974a(11) =5676a(12) =13531a(13) =14828a(14) =40744a(15) =27260a(16) =146845a(17) =55372a(18) =288174a(19) =177700a(20) =574867a(21) =204916a(22) =3721652a(23) =988332a(24) =3550621a(25) =3267452a(26) =11129590a(27) =4173196a(28) =46286551a(29) =7402156