18972

Appears in sequences

• a(n) = k such that the k-th triangular number is A068808(n).at n=24A067991
• Number of triangles in an n X n grid of squares with diagonals.at n=18A100583
• Numbers k such that the central binomial coefficient C(2k,k) is divisible by k^2.at n=34A121943
• a(n) = 1458*n + 18.at n=12A157505
• The number of homogeneous trisubstituted linear alkanes.at n=30A159938
• Even dodecagonal numbers: a(n) = 4*n*(5*n - 2).at n=31A193872
• Number of n X 5 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.at n=6A207388
• Number of 7Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.at n=4A207396
• Number of self-inverse permutations p on [n] where the maximal displacement of an element equals 2.at n=16A238913
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 5 6 or 7.at n=28A252574
• Number of (1+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 5 6 or 7.at n=7A252575
• a(n) = 15*n^2 - 13*n.at n=36A263226
• Numbers k such that (266*10^k + 1)/3 is prime.at n=32A269303
• Number of Hamiltonian regular graphs on n nodes.at n=11A283825
• Number of nX5 0..1 arrays with every element equal to 0, 2, 3 or 6 king-move adjacent elements, with upper left element zero.at n=13A297983
• Sum of all the parts in the partitions of n into 6 parts.at n=31A308867
• Number of separable partitions of n in which the number of distinct (repeatable) parts is > 4.at n=39A325719
• Expansion of Product_{i>=1, j>=1} (1 + x^(i*j*(j + 1)/2)).at n=43A327745