a(n) = 5*2^n + 5.

Terms

a(0) =10a(1) =15a(2) =25a(3) =45a(4) =85a(5) =165a(6) =325a(7) =645a(8) =1285a(9) =2565a(10) =5125a(11) =10245a(12) =20485a(13) =40965a(14) =81925a(15) =163845a(16) =327685a(17) =655365a(18) =1310725a(19) =2621445a(20) =5242885a(21) =10485765a(22) =20971525a(23) =41943045a(24) =83886085a(25) =167772165a(26) =335544325a(27) =671088645a(28) =1342177285a(29) =2684354565