OFFSET
1,4
COMMENTS
Rows numbered 3,6,9,12,15,... are, except for initial terms, multiples of (1,2,3,4,5,6,7,...)=A000027.
FORMULA
R(m,n) = m*n - ceiling(m*n/3). [Corrected by Stefano Spezia, Oct 28 2022]
EXAMPLE
Northwest corner:
0 1 2 2 3 4 4
1 2 4 5 6 8 9
2 4 6 8 10 12 14
2 5 8 10 13 16 18
3 6 10 13 16 20 23
MATHEMATICA
T[i_, j_]:=i*j-Ceiling[i*j/3]; Flatten[Table[T[m-n+1, n], {m, 12}, {n, m}]] (* Stefano Spezia, Oct 28 2022 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Clark Kimberling, Sep 06 2008
STATUS
approved