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A240694
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Partial products of divisors of n, cf. A027750.
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9
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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
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OFFSET
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1,3
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COMMENTS
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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
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LINKS
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Reinhard Zumkeller, Rows n = 1..1000 of table, flattened
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FORMULA
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T(n,1) = 1, T(n,k) = T(n,k-1) * A027750(n,k), 1 < k <= n.
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EXAMPLE
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. 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 .
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PROG
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(Haskell)
a240694 n k = a240694_tabf !! (n-1) !! (k-1)
a240694_row n = a240694_tabf !! (n-1)
a240694_tabf = map (scanl1 (*)) a027750_tabf
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CROSSREFS
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Cf. A000005 (row lengths), A240698.
Sequence in context: A176572 A168017 A293980 * A258643 A287561 A046924
Adjacent sequences: A240691 A240692 A240693 * A240695 A240696 A240697
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KEYWORD
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nonn,tabf
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AUTHOR
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Reinhard Zumkeller, Apr 10 2014
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STATUS
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approved
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