Multiplicity of K_3 in K_n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =2a(7) =4a(8) =8a(9) =12a(10) =20a(11) =28a(12) =40a(13) =52a(14) =70a(15) =88a(16) =112a(17) =136a(18) =168a(19) =200a(20) =240a(21) =280a(22) =330a(23) =380a(24) =440a(25) =500a(26) =572a(27) =644a(28) =728a(29) =812