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A143310
Triangle read by rows, A000012 * A127446, 1 <= k <= n.
1
1, 3, 2, 6, 2, 3, 10, 6, 3, 4, 15, 6, 3, 4, 5, 21, 12, 9, 4, 5, 6, 28, 12, 9, 4, 5, 6, 7, 36, 20, 9, 12, 5, 6, 7, 8, 45, 20, 18, 12, 5, 6, 7, 8, 9, 55, 30, 18, 12, 15, 6, 7, 8, 9, 10, 66, 30, 18, 12, 15, 6, 7, 8, 9, 10, 11, 78, 42, 30, 24, 15, 18, 7, 8, 9, 10, 11, 12
OFFSET
1,2
COMMENTS
Row sums = A143127: (1, 5, 11, 23, 33, 57, 71, ...).
FORMULA
Triangle read by rows, A000012 * A127446, 1 <= k <= n.
Conjecture: T(n,k) = Sum_{i=1..n} [i*k <= n]*i*k. - Mats Granvik, Feb 26 2021
EXAMPLE
First few rows of the triangle:
1;
3, 2;
6, 2, 3;
10, 6, 3, 4;
15, 6, 3, 4, 5;
21, 12, 9, 4, 5, 6;
28, 12, 9, 4, 5, 6, 7;
36, 20, 9, 12, 5, 6, 7, 8;
...
CROSSREFS
Sequence in context: A290798 A133519 A135223 * A131897 A061187 A248082
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Aug 06 2008
EXTENSIONS
Duplicate a(11)-a(15) terms removed by Mats Granvik, Feb 26 2021
STATUS
approved