G.f.: ( 1 + x + x^2 - x^3 - x^4 - sqrt( 1 - 2 x - 5 x^2 - 4 x^3 - 3 x^4 - 4 x^5 - x^6 + 2 x^7 + x^8 ) ) / ( 2 x (1 + x) ).

A050262

G.f.: ( 1 + x + x^2 - x^3 - x^4 - sqrt( 1 - 2 x - 5 x^2 - 4 x^3 - 3 x^4 - 4 x^5 - x^6 + 2 x^7 + x^8 ) ) / ( 2 x (1 + x) ).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =4a(4) =10a(5) =27a(6) =79a(7) =238a(8) =736a(9) =2322a(10) =7445a(11) =24190a(12) =79470a(13) =263534a(14) =880966a(15) =2965576a(16) =10044096a(17) =34202268a(18) =117026156a(19) =402139968a(20) =1387243056a(21) =4802307553a(22) =16677543678a(23) =58087052893a(24) =202855613896a(25) =710171007580

External references