OFFSET
1,2
COMMENTS
Rows numbered 3,6,9,12,15,... are, except for initial terms, multiples of (1,2,3,4,5,6,7,...) = A000027.
LINKS
Stefano Spezia, First 140 antidiagonals of the array, flattened
FORMULA
R(m,n) = m*n - floor(m*n/3).
EXAMPLE
Northwest corner:
1 2 2 3 4 4 5
2 3 4 6 7 8 10
2 4 6 8 10 12 14
3 6 8 11 14 16 18
4 7 10 14 17 20 24
See A143974.
MATHEMATICA
T[m_, n_]:=m*n-Floor[m*n/3]; Flatten[Table[T[n-k+1, k], {n, 12}, {k, n}]] (* Stefano Spezia, Oct 25 2022 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Clark Kimberling, Sep 06 2008
STATUS
approved