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 A245717 Triangle read by rows: T(n,k) = gcd(n,k^2), 1 <= k <= n. 3
 1, 1, 2, 1, 1, 3, 1, 4, 1, 4, 1, 1, 1, 1, 5, 1, 2, 3, 2, 1, 6, 1, 1, 1, 1, 1, 1, 7, 1, 4, 1, 8, 1, 4, 1, 8, 1, 1, 9, 1, 1, 9, 1, 1, 9, 1, 2, 1, 2, 5, 2, 1, 2, 1, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 4, 3, 4, 1, 12, 1, 4, 3, 4, 1, 12, 1, 1, 1, 1, 1, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened EXAMPLE First rows and their sums (A078430): .    1:   1                                           1 .    2:   1, 2                                        3 .    3:   1, 1, 3                                     5 .    4:   1, 4, 1, 4                                 10 .    5:   1, 1, 1, 1, 5                               9 .    6:   1, 2, 3, 2, 1,  6                          15 .    7:   1, 1, 1, 1, 1,  1, 7                       13 .    8:   1, 4, 1, 8, 1,  4, 1, 8                    28 .    9:   1, 1, 9, 1, 1,  9, 1, 1, 9                 33 .   10:   1, 2, 1, 2, 5,  2, 1, 2, 1, 10             27 .   11:   1, 1, 1, 1, 1,  1, 1, 1, 1,  1, 11         21 .   12:   1, 4, 3, 4, 1, 12, 1, 4, 3,  4,  1, 12     50 PROG (Haskell) a245717 n k = a245717_tabl !! (n-1) !! (k-1) a245717_row n = a245717_tabl !! (n-1) a245717_tabl = zipWith (zipWith gcd) a002024_tabl a133819_tabl CROSSREFS Cf. A050873, A002024, A133819, A078430 (row sums). Sequence in context: A320250 A089141 A336084 * A248008 A327981 A277606 Adjacent sequences:  A245714 A245715 A245716 * A245718 A245719 A245720 KEYWORD nonn,tabl AUTHOR Reinhard Zumkeller, Jul 30 2014 STATUS approved

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Last modified January 20 10:18 EST 2022. Contains 350471 sequences. (Running on oeis4.)