login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A282347 Square array read by antidiagonals downwards (see Comments for definition). 2
1, 2, 2, 3, 3, 4, 4, 4, 2, 7, 5, 5, 5, 4, 10, 6, 6, 6, 6, 7, 13, 7, 7, 7, 2, 9, 10, 16, 8, 8, 8, 8, 4, 12, 13, 19, 9, 9, 9, 9, 8, 7, 15, 16, 22, 10, 10, 10, 10, 6, 11, 10, 18, 19, 25, 11, 11, 11, 11, 11, 9, 14, 13, 21, 22, 28, 12, 12, 12, 12, 12, 6, 12, 17 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Define f(x(1),x(2),...,x(2k)) = (a(2k),x(1),x(2k-1),x(2),a(2k-1),a(3),...a(k-1)).  The array is defined by rows as follows.  row 1 = (1,2,3,4,5,...) = A000027.  To get from (row n) = (r(1),r(2),r(3),...) to (row n+1), the first 2n-2 terms are f(r(1),r(2),...,r(n-1),r(n+1),...,r(2n-1)), where r(n) is skipped, followed by (r(2n),r(2n+1),...) = (3n-1, 3n, 3n+1,...).

LINKS

Table of n, a(n) for n=1..74.

EXAMPLE

The corner of the square array begins:

1    2    3    4    5    6    7    8    9    10   11   12   13

2    3    4    5    6    7    8    9    10   11   12   13   14

4    2    5    6    7    8    9    10   11   12   13   14   15

7    4    6    2    8    9    10   11   12   13   14   15   16

10   7    9    4    8    6    11   12   13   14   15   16   17

13   10   12   7    11   9    6    4    14   15   16   17   18

16   13   15   10   14   12   4    7    6    11   17   18   19

19   16   18   13   17   15   11   10   6    14   7    12   20

MATHEMATICA

f[seq_] := Riffle[Take[Reverse[seq], #], Take[seq, #]] &[Floor[Length[seq]/2]];

rows = 200; row[1] = Table[n, {n, rows}];

Table[row[n + 1] = Flatten[{f[Take[row[n], 2 n - 1]], Drop[row[n], 2 n - 1]}], {n,    Floor[(rows - 1)/3 + 1]}];

TableForm[Table[Take[row[n], 20], {n, 1, 20}]]   (* A282347, array *)

Table[row[n][[n]], {n, 2 + Floor[(rows - 1)/3]}] (* A282347, sequence *)

(* Peter J. C. Moses, Feb 12 2017 *)

CROSSREFS

Cf. A035486, A282348 (diagonal).

Sequence in context: A074719 A079730 A035486 * A172397 A237815 A238701

Adjacent sequences:  A282344 A282345 A282346 * A282348 A282349 A282350

KEYWORD

nonn,tabl,easy

AUTHOR

Clark Kimberling, Feb 13 2017

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 25 18:12 EST 2018. Contains 299655 sequences. (Running on oeis4.)