Irregular triangle read by rows: T(n,k) = Sum_{i=0..k} (-1)^i * binomial(3*n+1,i) * binomial(k+3-i,3)^n, 0 <= k <= 3*(n-1).
A174266
Irregular triangle read by rows: T(n,k) = Sum_{i=0..k} (-1)^i * binomial(3*n+1,i) * binomial(k+3-i,3)^n, 0 <= k <= 3*(n-1).
Terms
- a(0) =1a(1) =1a(2) =9a(3) =9a(4) =1a(5) =1a(6) =54a(7) =405a(8) =760a(9) =405a(10) =54a(11) =1a(12) =1a(13) =243a(14) =6750a(15) =49682a(16) =128124a(17) =128124a(18) =49682a(19) =6750a(20) =243a(21) =1a(22) =1a(23) =1008a(24) =83736a(25) =1722320a(26) =12750255a(27) =40241088a(28) =58571184a(29) =40241088
External references
- oeis: A174266