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A143271
Triangle read by rows: A130209 * A000012 * A127648.
1
1, 2, 4, 2, 4, 6, 3, 6, 9, 12, 2, 4, 6, 8, 10, 4, 8, 12, 16, 20, 24, 2, 4, 6, 8, 10, 12, 14, 4, 8, 12, 16, 20, 24, 28, 32, 3, 6, 9, 12, 15, 18, 21, 24, 27, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72
OFFSET
1,2
COMMENTS
Row sums = A143272: (1, 6, 12, 30, 30, 84, 56, ...).
Left border = A000005: (1, 2, 2, 3, 2, 4, 2, 4, 3, ...).
FORMULA
T(n,k) = d(n)*k.
EXAMPLE
First few rows of the triangle =
1;
2, 4;
2, 4, 6;
3, 6, 9, 12;
2, 4, 6, 8, 10;
4, 8, 12, 16, 20, 24;
2, 4, 6, 8, 10, 12, 14;
...
T(5,3) = 6 = 2*3 = d(5)*3.
PROG
(PARI) tabl(nn) = for (n=1, nn, for (k=1, n, print1(numdiv(n)*k, ", "))); \\ Michel Marcus, Jun 05 2023
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Aug 03 2008
EXTENSIONS
a(62) corrected by Georg Fischer, Jun 05 2023
STATUS
approved