a(n) = a(n-2)*2 + floor(sqrt(a(n-1))).

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =3a(5) =7a(6) =8a(7) =16a(8) =20a(9) =36a(10) =46a(11) =78a(12) =100a(13) =166a(14) =212a(15) =346a(16) =442a(17) =713a(18) =910a(19) =1456a(20) =1858a(21) =2955a(22) =3770a(23) =5971a(24) =7617a(25) =12029a(26) =15343a(27) =24181a(28) =30841a(29) =48537