Number of connected induced subgraphs in the n-sun graph.

Terms

a(0) =3a(1) =14a(2) =47a(3) =164a(4) =577a(5) =2046a(6) =7275a(7) =25896a(8) =92213a(9) =328402a(10) =1169599a(11) =4165564a(12) =14835849a(13) =52838630a(14) =188187539a(15) =670239824a(16) =2387094493a(17) =8501763066a(18) =30279478119a(19) =107841960420a(20) =384084837425