Number of (n,4) Freiman-Wyner sequences.

Terms

a(0) =18a(1) =36a(2) =70a(3) =134a(4) =258a(5) =498a(6) =960a(7) =1850a(8) =3566a(9) =6874a(10) =13250a(11) =25540a(12) =49230a(13) =94894a(14) =182914a(15) =352578a(16) =679616a(17) =1310002a(18) =2525110a(19) =4867306a(20) =9382034a(21) =18084452a(22) =34858902a(23) =67192694a(24) =129518082a(25) =249654130a(26) =481223808a(27) =927588714a(28) =1787984734a(29) =3446451386