a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026648.
A026974
a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026648.
Terms
- a(0) =1a(1) =12a(2) =77a(3) =450a(4) =2154a(5) =11592a(6) =51060a(7) =261720a(8) =1106790a(9) =5562216a(10) =23051943a(11) =114491286a(12) =468950860a(13) =2313509520a(14) =9409147640a(15) =46221336720a(16) =187136146566a(17) =916762621320
External references
- oeis: A026974