Heptanacci-Lucas numbers.

Terms

a(0) =7a(1) =1a(2) =3a(3) =7a(4) =15a(5) =31a(6) =63a(7) =127a(8) =247a(9) =493a(10) =983a(11) =1959a(12) =3903a(13) =7775a(14) =15487a(15) =30847a(16) =61447a(17) =122401a(18) =243819a(19) =485679a(20) =967455a(21) =1927135a(22) =3838783a(23) =7646719a(24) =15231991a(25) =30341581a(26) =60439343a(27) =120393007a(28) =239818559a(29) =477709983