

A273823


Table read by rows: the nth row is the list of numbers to the left of n in the natural numbers read by antidiagonals.


5



1, 2, 1, 3, 4, 2, 1, 5, 3, 6, 7, 4, 2, 1, 8, 5, 3, 9, 6, 10, 11, 7, 4, 2, 1, 12, 8, 5, 3, 13, 9, 6, 14, 10, 15, 16, 11, 7, 4, 2, 1, 17, 12, 8, 5, 3, 18, 13, 9, 6, 19, 14, 10, 20, 15, 21, 22, 16, 11, 7, 4, 2, 1, 23, 17, 12, 8, 5, 3, 24, 18, 13, 9, 6, 25, 19, 14
(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: [1]
Row 3: []
Row 4: [2, 1]
Row 5: [3]
Row 6: []
Row 7: [4, 2, 1]
Row 8: [5, 3]
Row 9: [6]


MATHEMATICA

nn = 32; t = Table[(n^2  n)/2 + Accumulate@ Range[n  1, 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)
a273823 n = genericIndex a273823_list (n  1)
a273823_list = concatMap a273823_row [1..]
a273823_tabf = map a273823_row [1..]
a273823_row n
 a_i == 0 = []
 otherwise = a_i : a273823_row a_i where
a_i = a271439 n


CROSSREFS

Cf. A000027, A025581 (row length), A269526, A271439, A273824, A273825, A274079, A274080.
Sequence in context: A341231 A334081 A125158 * A112384 A248514 A123390
Adjacent sequences: A273820 A273821 A273822 * A273824 A273825 A273826


KEYWORD

nonn,tabf,look


AUTHOR

Peter Kagey, Jun 08 2016


STATUS

approved



