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A274079
Table read by rows: the n-th row is the list of numbers diagonally up and to the right of n in the natural numbers read by antidiagonals.
5
2, 4, 5, 4, 7, 8, 7, 9, 8, 7, 11, 12, 11, 13, 12, 11, 14, 13, 12, 11, 16, 17, 16, 18, 17, 16, 19, 18, 17, 16, 20, 19, 18, 17, 16, 22, 23, 22, 24, 23, 22, 25, 24, 23, 22, 26, 25, 24, 23, 22, 27, 26, 25, 24, 23, 22, 29, 30, 29, 31, 30, 29, 32, 31, 30, 29, 33, 32
OFFSET
1,1
EXAMPLE
A000027 read by antidiagonals is:
1 2 4 7
3 5 8
6 9
...
Thus:
Row 1: []
Row 2: []
Row 3: [2]
Row 4: []
Row 5: [4]
Row 6: [5, 4]
Row 7: []
Row 8: [7]
Row 9: [8, 7]
MATHEMATICA
Table[Reverse@ Range[SelectFirst[Reverse@ #, # < n &] + 1, n - 1] - 1, {n, 2, 35}] &[Accumulate@ Range[0, 15] + 1] // Flatten (* Michael De Vlieger, Jun 10 2016, Version 10 *)
PROG
(Haskell)
a274079 n = a274079_list !! (n - 1)
a274079_list = concatMap a274079_row [1..]
a274079_tabf = map a274079_row [1..]
a274079_row n = [n-1, n-2..n - a002262 (n - 1)]
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Peter Kagey, Jun 09 2016
STATUS
approved