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A240694 Partial products of divisors of n, cf. A027750. 6
1, 1, 2, 1, 3, 1, 2, 8, 1, 5, 1, 2, 6, 36, 1, 7, 1, 2, 8, 64, 1, 3, 27, 1, 2, 10, 100, 1, 11, 1, 2, 6, 24, 144, 1728, 1, 13, 1, 2, 14, 196, 1, 3, 15, 225, 1, 2, 8, 64, 1024, 1, 17, 1, 2, 6, 36, 324, 5832, 1, 19, 1, 2, 8, 40, 400, 8000, 1, 3, 21, 441, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

T(n,1) = 1;

T(n,2) = A020639(n), n > 1;

T(n,A000005(n)) = A007955(n);

T(n,A000005(n)-1) = A007956(n), n > 1.

Triangle read by rows in which row n lists the partial products of divisors of n. - Omar E. Pol, Apr 12 2014

LINKS

Reinhard Zumkeller, Rows n = 1..1000 of table, flattened

FORMULA

T(n,1) = 1, T(n,k) = T(n,k-1) * A027750(n,k), 1 < k <= n.

EXAMPLE

.    n |  n-th row of A240694     |  n-th row of A027750

.  ----+--------------------------+---------------------

.    1 |  1                       |  1

.    2 |  1, 2                    |  1, 2

.    3 |  1, 3                    |  1, 3

.    4 |  1, 2, 8                 |  1, 2, 4

.    5 |  1, 5                    |  1, 5

.    6 |  1, 2, 6, 36             |  1, 2, 3, 6

.    7 |  1, 7                    |  1, 7

.    8 |  1, 2, 8, 64             |  1, 2, 4, 8

.    9 |  1, 3, 27                |  1, 3, 9

.   10 |  1, 2, 10, 100           |  1, 2, 5, 10

.   11 |  1, 11                   |  1, 11

.   12 |  1, 2, 6, 24, 144, 1728  |  1, 2, 3, 4, 6, 12

.   13 |  1, 13                   |  1, 13 .

PROG

(Haskell)

a240694 n k = a240694_tabf !! (n-1) !! (k-1)

a240694_row n = a240694_tabf !! (n-1)

a240694_tabf = map (scanl1 (*)) a027750_tabf

CROSSREFS

Cf. A000005 (row lengths), A240698.

Sequence in context: A176572 A168017 A293980 * A258643 A287561 A046924

Adjacent sequences:  A240691 A240692 A240693 * A240695 A240696 A240697

KEYWORD

nonn,tabf

AUTHOR

Reinhard Zumkeller, Apr 10 2014

STATUS

approved

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Last modified December 15 03:08 EST 2017. Contains 296020 sequences.