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A060734 Natural numbers written as a square array ending in last row from left to right and rightmost column from bottom to top are read by antidiagonals downwards. 6
1, 4, 2, 9, 3, 5, 16, 8, 6, 10, 25, 15, 7, 11, 17, 36, 24, 14, 12, 18, 26, 49, 35, 23, 13, 19, 27, 37, 64, 48, 34, 22, 20, 28, 38, 50, 81, 63, 47, 33, 21, 29, 39, 51, 65, 100, 80, 62, 46, 32, 30, 40, 52, 66, 82, 121, 99, 79, 61, 45, 31, 41, 53, 67, 83, 101 (list; table; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

A simple permutation of natural numbers.

Parity of the sequence is given by A057211 (n-th run has length n). [From Jeremy Gardiner (jeremy.gardiner(AT)btinternet.com), Dec 26 2008]

The square with corners T(1,1)=1 and T(n,n)=n^2-n+1 is occupied by the numbers 1,2,...,n^2. - Clark Kimberling, Feb 01 2011

LINKS

Index entries for sequences that are permutations of the natural numbers

Alois P. Heinz, Table of n, a(n) for n = 1..10011

FORMULA

T(n,k) = (n-1)^2+k, T(k, n)=n^2+1-k, 1 <= k <= n.

T(1,k) = k^2 (A000290). - Clark Kimberling, Feb 01 2011

T(n,n) = n^2-n+1 (A002061) - Clark Kimberling, Feb 01 2011

T(n,1) = (n-1)^2+1 (A002522). - Clark Kimberling, Feb 01 2011

EXAMPLE

Northwest corner:

.1  4  9 16 ..  => a(1) =  1

.2  3  8 15 ..  => a(2) =  4, a(3) = 2

.5  6  7 14 ..  => a(4) =  9, a(5) = 3, a(6) = 5

10 11 12 13 ..  => a(7) = 16, a(8) = 8, a(9) = 6, a(10)=10

MAPLE

T:= (n, k)-> `if` (n<=k, k^2-n+1, (n-1)^2+k):

seq (seq (T(n, d-n), n=1..d-1), d=2..15);

MATHEMATICA

f[n_, k_]:=k^2-n+1/; k>=n;

f[n_, k_]:=(n-1)^2+k/; k<n;

TableForm[Table[f[n, k], {n, 1, 10}, {k, 1, 15}]]

Table[f[n-k+1, k], {n, 14}, {k, n, 1, -1}]//Flatten (* Clark Kimberling, Feb 01 2011 *)

CROSSREFS

Cf. A060736. Inverse: A064790.

Cf. A185725, A185726, A185728. - Clark Kimberling, Feb 01 2011

Sequence in context: A201574 A077809 A201281 * A075594 A076022 A064421

Adjacent sequences:  A060731 A060732 A060733 * A060735 A060736 A060737

KEYWORD

nonn,tabl

AUTHOR

Frank Ellermann (Frank.Ellermann(AT)t-online.de), Apr 23 2001

EXTENSIONS

Corrected by Jeremy Gardiner (jeremy.gardiner(AT)btinternet.com), Dec 26 2008

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.