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A170950
Inverse permutation to A170949.
5
1, 3, 2, 4, 7, 6, 8, 5, 9, 13, 12, 14, 11, 15, 10, 16, 21, 20, 22, 19, 23, 18, 24, 17, 25, 31, 30, 32, 29, 33, 28, 34, 27, 35, 26, 36, 43, 42, 44, 41, 45, 40, 46, 39, 47, 38, 48, 37, 49, 57, 56, 58, 55, 59, 54, 60, 53, 61, 52, 62, 51, 63, 50, 64, 73, 72, 74, 71, 75, 70, 76, 69, 77, 68, 78
OFFSET
1,2
COMMENTS
a(A002522(n-1)) = A002061(n); a(A002061(n)) = A174114(n). - Reinhard Zumkeller, Mar 08 2010
Row sums are n^3+(n+1)^3 [A005898](1,9,35,91,189,...). - Vincenzo Librandi, Feb 22 2010
The even central polygonal numbers divided by 2 give the central column of the triangle. - Omar E. Pol, Aug 16 2011
REFERENCES
J. H. Conway, Personal communication, Feb 19 2010
EXAMPLE
1
3 2 4
7 6 8 5 9
13 12 14 11 15 10 16
21 20 22 19 23 18 24 17 25
31 30 32 29 33 28 34 27 35 26 36
43 42 44 41 45 40 46 39 47 38 48 37 49
57 56 58 55 59 54 60 53 61 52 62 51 63 50 64
73 72 74 71 75 70 76 69 77 68 78 67 79 66 80 65 81
CROSSREFS
Sequence in context: A105025 A129594 A214416 * A276954 A276944 A300501
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Feb 21 2010
STATUS
approved