Row sums of array T in A055818; twice the odd-indexed Fibonacci numbers after initial term.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =26a(5) =68a(6) =178a(7) =466a(8) =1220a(9) =3194a(10) =8362a(11) =21892a(12) =57314a(13) =150050a(14) =392836a(15) =1028458a(16) =2692538a(17) =7049156a(18) =18454930a(19) =48315634a(20) =126491972a(21) =331160282a(22) =866988874a(23) =2269806340a(24) =5942430146a(25) =15557484098a(26) =40730022148a(27) =106632582346