a(n) = Sum_{k=0 .. n} Sum_{j=0 .. k} tan(j*Pi/(1 + 2*k))^(2*(n - k)). Antidiagonal sums of A377657.
A377658
a(n) = Sum_{k=0 .. n} Sum_{j=0 .. k} tan(j*Pi/(1 + 2*k))^(2*(n - k)). Antidiagonal sums of A377657.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =23a(4) =143a(5) =1344a(6) =16476a(7) =248509a(8) =4519021a(9) =97094158a(10) =2419043330a(11) =68973522675
External references
- oeis: A377658