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A182469
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Triangle read by rows in which row n lists the odd divisors of n.
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21
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1, 1, 1, 3, 1, 1, 5, 1, 3, 1, 7, 1, 1, 3, 9, 1, 5, 1, 11, 1, 3, 1, 13, 1, 7, 1, 3, 5, 15, 1, 1, 17, 1, 3, 9, 1, 19, 1, 5, 1, 3, 7, 21, 1, 11, 1, 23, 1, 3, 1, 5, 25, 1, 13, 1, 3, 9, 27, 1, 7, 1, 29, 1, 3, 5, 15, 1, 31, 1, 1, 3, 11, 33, 1, 17, 1, 5, 7, 35, 1
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OFFSET
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1,4
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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The triangle begins:
. 1 {1}
. 2 {1}
. 3 {1,3}
. 4 {1}
. 5 {1,5}
. 6 {1,3}
. 7 {1,7}
. 8 {1}
. 9 {1,3,9}
. 10 {1,5}
. 11 {1,11}
. 12 {1,3}
. 13 {1,13}
. 14 {1,7}
. 15 {1,3,5,15}
. 16 {1} .
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MATHEMATICA
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Flatten[Table[Select[Divisors[n], OddQ], {n, 40}]] (* Harvey P. Dale, Aug 13 2012 *)
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PROG
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(Haskell)
a182469 n k = a182469_tabf !! (n-1) !! (k-1)
a182469_row = a027750_row . a000265
a182469_tabf = map a182469_row [1..]
(PARI) tabf(nn) = {for (n=1, nn, fordiv(n, d, if (d%2, print1(d, ", "))); print(); ); } \\ Michel Marcus, Apr 22 2017
(Python)
from sympy import divisors
def row(n):
return [d for d in divisors(n) if d % 2]
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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