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.

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

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