Number of 3 X 3 X 3 arrays M_ijk (1 <= i,j,k <= 3) with entries satisfying 0 <= M_ijk <= n and all line sums equal to n.
A002721
Number of 3 X 3 X 3 arrays M_ijk (1 <= i,j,k <= 3) with entries satisfying 0 <= M_ijk <= n and all line sums equal to n.
Terms
- a(0) =1a(1) =12a(2) =132a(3) =847a(4) =3921a(5) =14506a(6) =45402a(7) =124707a(8) =308407a(9) =699766a(10) =1477686a(11) =2936517a(12) =5540107a(13) =9993192a(14) =17333536a(15) =29048541a(16) =47220357a(17) =74703832a(18) =115341952a(19) =174223731a(20) =257989821a(21) =375191422a(22) =536708382a(23) =756232687a(24) =1050823851a(25) =1441543026a(26) =1954172962
External references
- oeis: A002721