A170950 Inverse permutation to A170949.

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

Links

R. Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences that are permutations of the natural numbers [From Reinhard Zumkeller, Mar 08 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

Adjacent sequences: A170947 A170948 A170949 * A170951 A170952 A170953

Keyword

nonn,tabf

Author

N. J. A. Sloane, Feb 21 2010

Status

approved