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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A141396 Triangle read by rows, antidiagonals of a multiplication table: 3^n * (numbers not multiples of 3). 3
1, 2, 3, 4, 6, 9, 5, 12, 18, 27, 7, 15, 36, 54, 81, 8, 21, 45, 108, 162, 243, 10, 24, 63, 135, 324, 486, 729, 11, 30, 72, 189, 405, 972, 1458, 2187, 13, 33, 90, 216, 567, 1215, 2916, 4374, 6561, 14, 39, 99, 270, 648, 1701, 3645, 8748, 13122, 19683, 16, 42, 117, 297 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Ternary representation of terms in n-th row have n rightmost adjacent zeros.

Row sums = A141397: (1, 5, 19 62, 193, 587, ...).

LINKS

Ivan Neretin, Table of n, a(n) for n = 0..5049

FORMULA

Triangle read by rows, descending antidiagonals of the multiplication table: (top row, numbers not multiples of 3); leftmost column, 3^n.

EXAMPLE

The array begins:

   1,   2,   4,   5,   7, ...

   3,   6,  12,  15,  21, ...

   9,  18,  36,  45,  63, ...

  27,  54, 108, 135, 189, ...

  81, 162, 324, 405, 567, ...

  ...

Descending antidiagonals of the array give

   1;

   2,    3;

   4,    6,    9;

   5,   12,   18,   27;

   7,   15,   36,   54,   81;

   8,   21,   45,  108,  162,  243;

  10,   24,   63,  135,  324,  486,  729;

  11,   30,   72,  189,  405,  972, 1458, 2187;

  ...

MATHEMATICA

Flatten[Table[3^k*Quotient[(3 (m - k) - 1), 2], {m, 0, 10}, {k, 0, m - 1}]] (* Ivan Neretin, Nov 26 2016 *)

CROSSREFS

Cf. A001651, A141397.

Sequence in context: A233559 A285332 A185290 * A159849 A098168 A306441

Adjacent sequences:  A141393 A141394 A141395 * A141397 A141398 A141399

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jun 29 2008

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 21 14:10 EDT 2019. Contains 328301 sequences. (Running on oeis4.)