Number of 1's in n-th term of A007651.

Terms

a(0) =1a(1) =2a(2) =1a(3) =3a(4) =4a(5) =3a(6) =4a(7) =6a(8) =8a(9) =12a(10) =13a(11) =18a(12) =24a(13) =33a(14) =39a(15) =52a(16) =67a(17) =88a(18) =113a(19) =155a(20) =211a(21) =264a(22) =331a(23) =455a(24) =596a(25) =762a(26) =1000a(27) =1288a(28) =1688a(29) =2222