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A213944
Triangle read by rows, with column k defined by partial sums of the finite sequence that contains k three times.
1
1, 2, 0, 3, 2, 0, 3, 4, 0, 0, 3, 6, 3, 0, 0, 3, 6, 6, 0, 0, 0, 3, 6, 9, 4, 0, 0, 0, 3, 6, 9, 8, 0, 0, 0, 0, 3, 6, 9, 12, 5, 0, 0, 0, 0, 3, 6, 9, 12, 10, 0, 0, 0, 0, 0, 3, 6, 9, 12, 15, 6, 0, 0, 0, 0, 0, 3, 6, 9, 12, 15, 12
OFFSET
1,2
LINKS
FORMULA
T(n,k) = 0 if 2k > n+1. T(n,k) = k if 2k=n+1. T(n,k)=2k if 2k=n. T(n,k) = 3k if 2k <= n-1.
EXAMPLE
First few rows of the triangle are:
1;
2, 0;
3, 2, 0;
3, 4, 0, 0;
3, 6, 3, 0, 0;
3, 6, 6, 0, 0, 0;
3, 6, 9, 4, 0, 0, 0;
3, 6, 9, 8, 0, 0, 0, 0;
3, 6, 9, 12, 5, 0, 0, 0, 0;
3, 6, 9, 12, 10, 0, 0, 0, 0, 0;
3, 6, 9, 12, 15, 6, 0, 0, 0, 0, 0;
3, 6, 9, 12, 15, 12, 0, 0, 0, 0, 0, 0;
...
MATHEMATICA
fs[n_, k_]:=Which[2k>n+1, 0, 2k==n+1, k, 2k==n, 2k, 2k<=n-1, 3k]; Flatten[ Table[ fs[n, k], {n, 15}, {k, n}]] (* Harvey P. Dale, Mar 06 2013 *)
CROSSREFS
Cf. A001318 (row sums)
Sequence in context: A120854 A035159 A103489 * A127479 A284124 A187637
KEYWORD
nonn,tabl,less,easy
AUTHOR
Gary W. Adamson, Jun 25 2012
STATUS
approved