login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A129765 Triangle, (1, 1, 2, 2, 2, ...) in every column. 2
1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
Row sums = A004277, (1, 2, 4, 6, 8, 10, ...). Binomial transform of (1, 1, 2, 2, 2, ...) = A000325, starting (1, 2, 5, 12, 27, 58, ...). Binomial transform of A130196 = A130197, a triangle with row sums = the Cullen numbers, A002064.
LINKS
FORMULA
Triangle, (1, 1, 2, 2, 2, ...) in every column. By rows, (1; 1, 1; 2, 1, 1; ...), continuing with (n-2) 2's followed by two 1's. Inverse of A000012 as an infinite lower triangular matrix (all 1's and the rest zeros), signed by columns: (+ - - + + - -, ...).
EXAMPLE
First few rows of the triangle:
1;
1, 1;
2, 1, 1;
2, 2, 1, 1;
2, 2, 2, 1, 1;
...
MAPLE
A129765 := proc(n, m) if abs(n-m)<2 then 1 ; else 2 ; end if ; end proc:
for n from 1 to 18 do for m from 1 to n do printf("%d, ", A129765(n, m)) ; od ; od ; # R. J. Mathar, Jun 08 2007
MATHEMATICA
Table[PadLeft[{1, 1}, n, 2], {n, 20}]//Flatten (* Harvey P. Dale, May 20 2019 *)
CROSSREFS
Sequence in context: A174886 A157415 A154325 * A143187 A348042 A143209
KEYWORD
nonn,tabl,easy
AUTHOR
Gary W. Adamson, May 16 2007
EXTENSIONS
More terms from R. J. Mathar, Jun 08 2007
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 29 10:50 EST 2024. Contains 370425 sequences. (Running on oeis4.)