Smallest triangular number with Hamming weight n (i.e., with exactly n 1's when written in binary).

Terms

a(0) =0a(1) =1a(2) =3a(3) =21a(4) =15a(5) =55a(6) =190a(7) =253a(8) =703a(9) =3003a(10) =5886a(11) =13695a(12) =4095a(13) =49141a(14) =106491a(15) =192510a(16) =784378a(17) =1915903a(18) =3407355a(19) =5240703a(20) =15986685a(21) =30400503a(22) =48201471a(23) =124780503a(24) =247431135a(25) =602930175a(26) =1608777726a(27) =4290575295a(28) =7482375615a(29) =15938355070