Number of connected planar graphs with at most n edges.

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =11a(5) =23a(6) =53a(7) =132a(8) =359a(9) =1068a(10) =3386a(11) =11435a(12) =40807a(13) =152807a(14) =597662a(15) =2430734a(16) =10237458a(17) =44489603a(18) =198831994a(19) =911063459