a(n) = a(n-1) + a(n-2) + gcd(a(n-1), a(n-2)) for n > 1; a(0)=1, a(1)=1.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =9a(5) =15a(6) =27a(7) =45a(8) =81a(9) =135a(10) =243a(11) =405a(12) =729a(13) =1215a(14) =2187a(15) =3645a(16) =6561a(17) =10935a(18) =19683a(19) =32805a(20) =59049a(21) =98415a(22) =177147a(23) =295245a(24) =531441a(25) =885735a(26) =1594323a(27) =2657205a(28) =4782969a(29) =7971615