First differences of Shallit sequence S(3,7) (A020730).

Terms

a(0) =3a(1) =4a(2) =10a(3) =25a(4) =62a(5) =154a(6) =383a(7) =952a(8) =2366a(9) =5881a(10) =14618a(11) =36335a(12) =90315a(13) =224489a(14) =557995a(15) =1386965a(16) =3447471a(17) =8569111a(18) =21299574a(19) =52942697a(20) =131595551a(21) =327096843a(22) =813039224a(23) =2020908468a(24) =5023215259a(25) =12485816125a(26) =31035023639a(27) =77141348442a(28) =191744259926a(29) =476603818278