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A079297 Triangle read by rows: the k-th column is an arithmetic progression with difference 2k-1 and the top entry is the hexagonal number k*(2*k-1) (A000384). 0
1, 2, 6, 3, 9, 15, 4, 12, 20, 28, 5, 15, 25, 35, 45, 6, 18, 30, 42, 54, 66, 7, 21, 35, 49, 63, 77, 91, 8, 24, 40, 56, 72, 88, 104, 120, 9, 27, 45, 63, 81, 99, 117, 135, 153, 10, 30, 50, 70, 90, 110, 130, 150, 170, 190, 11, 33, 55, 77, 99, 121, 143, 165, 187, 209, 231, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The n-th row consists of the odd multiples of n from n*1 to n*(2n-1).
REFERENCES
R. Honsberger, Ingenuity in Math., Random House, 1970, p. 88.
LINKS
FORMULA
n-th row adds to n^3.
a(n, k) = n(2k-1) for 1<=k<=n.
EXAMPLE
Triangle begins:
1
2 6
3 9 15
4 12 20 28
5 15 25 35 45
6 18 30 42 54 66
MATHEMATICA
Flatten[Table[n(2k-1), {n, 1, 12}, {k, 1, n}]]
CROSSREFS
Sequence in context: A078340 A308541 A136190 * A276941 A143219 A109465
KEYWORD
nonn,tabl,easy
AUTHOR
N. J. A. Sloane, Mar 04 2003
EXTENSIONS
More terms from Dean Hickerson, Apr 06, 2003
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)