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 A273824 Table read by rows: the n-th row is the list of numbers above n in the table of natural numbers read by antidiagonals. 5
 1, 2, 3, 1, 4, 5, 2, 6, 3, 1, 7, 8, 4, 9, 5, 2, 10, 6, 3, 1, 11, 12, 7, 13, 8, 4, 14, 9, 5, 2, 15, 10, 6, 3, 1, 16, 17, 11, 18, 12, 7, 19, 13, 8, 4, 20, 14, 9, 5, 2, 21, 15, 10, 6, 3, 1, 22, 23, 16, 24, 17, 11, 25, 18, 12, 7, 26, 19, 13, 8, 4, 27, 20, 14, 9, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Peter Kagey, Table of n, a(n) for n = 1..10000 EXAMPLE A000027 read by antidiagonals is: 1 2 4 7 3 5 8 6 9 ... Thus: Row 1: [] Row 2: [] Row 3: [1] Row 4: [] Row 5: [2] Row 6: [3, 1] Row 7: [] Row 8: [4] Row 9: [5, 2] MATHEMATICA nn = 35; t = Transpose@ Table[(n^2 - n)/2 + Accumulate@ Range[n - 1, n + Ceiling[(Sqrt[9 + 8 nn] - 3)/2]] + 1, {n, Ceiling[(Sqrt[9 + 8 nn] - 3)/2] + 1}]; Table[Reverse@ Take[t[[#1]], #2 - 1] & @@ Flatten@ Position[t, n], {n, nn}] // Flatten (* Michael De Vlieger, Jun 10 2016 *) PROG (Haskell) a273824 n = genericIndex a273824_list (n - 1) a273824_list = concatMap a273824_row [1..] a273824_tabf = map a273824_row [1..] a273824_row n   | a_i == 0  = []   | otherwise = a_i : a273824_row a_i where     a_i = a271439 (n - 1) CROSSREFS Cf. A000027, A269526, A271439, A273823, A273825, A274079, A274080. Sequence in context: A131225 A221919 A341971 * A137671 A256946 A285715 Adjacent sequences:  A273821 A273822 A273823 * A273825 A273826 A273827 KEYWORD nonn,tabf AUTHOR Peter Kagey, Jun 08 2016 STATUS approved

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Last modified April 23 06:38 EDT 2021. Contains 343201 sequences. (Running on oeis4.)