a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026725.
A027208
a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026725.
Terms
- a(0) =1a(1) =4a(2) =19a(3) =72a(4) =338a(5) =1289a(6) =6027a(7) =23117a(8) =107746a(9) =415058a(10) =1929383a(11) =7456777a(12) =34584731a(13) =134005510a(14) =620344059a(15) =2408498148a(16) =11131638368a(17) =43289074671a(18) =199800878749a(19) =778025282080
External references
- oeis: A027208