a(n) = Sum_{i=1..n} (i-1)*T(i)^2, where T(i) = A000073(i) is the i-th tribonacci number.
A337284
a(n) = Sum_{i=1..n} (i-1)*T(i)^2, where T(i) = A000073(i) is the i-th tribonacci number.
Terms
- a(0) =0a(1) =1a(2) =3a(3) =15a(4) =79a(5) =324a(6) =1338a(7) =5370a(8) =20858a(9) =79907a(10) =301917a(11) =1127753a(12) =4175945a(13) =15347222a(14) =56045572a(15) =203563012a(16) =735880196a(17) =2649245173a(18) =9502874215a(19) =33976624115a(20) =121128306995a(21) =430701953720
External references
- oeis: A337284