a(n) = n*A259968(n).

Terms

a(0) =0a(1) =1a(2) =2a(3) =9a(4) =24a(5) =50a(6) =102a(7) =210a(8) =424a(9) =837a(10) =1630a(11) =3146a(12) =6024a(13) =11453a(14) =21644a(15) =40695a(16) =76176a(17) =142035a(18) =263916a(19) =488870a(20) =903060a(21) =1663998a(22) =3059166a(23) =5612483a(24) =10277448a(25) =18787150a(26) =34287916a(27) =62485371a(28) =113715448a(29) =206683725