Sum along upward diagonal of Pascal triangle from halfway point.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =7a(7) =14a(8) =26a(9) =46a(10) =51a(11) =97a(12) =176a(13) =309a(14) =365a(15) =674a(16) =1204a(17) =2098a(18) =2587a(19) =4685a(20) =8273a(21) =14323a(22) =18228a(23) =32551a(24) =56967a(25) =98086a(26) =127921a(27) =226007a(28) =392688a(29) =672959