Maximal number of edges in n-node graph of girth at least 5.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =6a(6) =8a(7) =10a(8) =12a(9) =15a(10) =16a(11) =18a(12) =21a(13) =23a(14) =26a(15) =28a(16) =31a(17) =34a(18) =38a(19) =41a(20) =44a(21) =47a(22) =50a(23) =54a(24) =57a(25) =61a(26) =65a(27) =68a(28) =72a(29) =76