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 A182469 Triangle read by rows in which row n lists the odd divisors of n. 21
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Row lengths: A001227; row sums: A000593; row products: A136655; n-th row = intersection of A005408 and of n-th row of A027750; A000265(n) = T(n,A001227(n)). LINKS Reinhard Zumkeller, Rows n = 1..2500 of triangle, flattened FORMULA T(n,k) = A027750(A000265(n),k), 1 <= k <= A001227(n). EXAMPLE 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} . MATHEMATICA Flatten[Table[Select[Divisors[n], OddQ], {n, 40}]] (* Harvey P. Dale, Aug 13 2012 *) PROG (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 a(n): return [d for d in divisors(n) if d%2==1] for n in xrange(1, 21): print a(n) # Indranil Ghosh, Apr 22 2017 CROSSREFS Cf. A027750, A050999, A051000, A037283, A037284, A037285, A171565. Sequence in context: A046230 A046229 A255670 * A261697 A261698 A124738 Adjacent sequences:  A182466 A182467 A182468 * A182470 A182471 A182472 KEYWORD nonn,tabf AUTHOR Reinhard Zumkeller, Apr 30 2012 STATUS approved

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Last modified January 21 11:19 EST 2019. Contains 319352 sequences. (Running on oeis4.)