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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A066686 Array T(i,j) read by antidiagonals, where T(i,j) is the concatenation of i and j (1<=i, 1<=j). 2
11, 12, 21, 13, 22, 31, 14, 23, 32, 41, 15, 24, 33, 42, 51, 16, 25, 34, 43, 52, 61, 17, 26, 35, 44, 53, 62, 71, 18, 27, 36, 45, 54, 63, 72, 81, 19, 28, 37, 46, 55, 64, 73, 82, 91, 110, 29, 38, 47, 56, 65, 74, 83, 92, 101, 111, 210, 39, 48, 57, 66, 75, 84, 93, 102, 111 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The element at T(i,j) is the {(i+j-1)(i+j-2)/2 + i}-th element read in the sequence.

LINKS

Table of n, a(n) for n=1..66.

Alexander Bogomolny, What is a number?

Boris Putievskiy, Transformations [Of] Integer Sequences And Pairing Functions, arXiv preprint arXiv:1212.2732, 2012.

EXAMPLE

The array begins

11 12 13 14 15 16 17 18 19 110 ...

21 22 23 24 25 26 27 28 29 210 ...

31 32 33 34 35 36 37 38 39 310 ...

41 42 43 44 45 46 47 48 49 410 ...

MATHEMATICA

a = {}; Do[ a = Append[a, ToExpression[ StringJoin[ ToString[k], ToString[n - k]]]], {n, 2, 13}, {k, 1, n - 1} ]; a

CROSSREFS

Sequence in context: A057303 A121979 A109372 * A125887 A107478 A153146

Adjacent sequences:  A066683 A066684 A066685 * A066687 A066688 A066689

KEYWORD

easy,nonn,tabl,base

AUTHOR

Robert G. Wilson v, Jan 11 2002

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 December 13 09:05 EST 2017. Contains 295957 sequences.