login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143544 Triangle read by rows, T(n,k) = 2 if n is prime, 1 otherwise; 1<=k<=n. 1
1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row sums = A143545: (1, 4, 6, 4, 10, 6, 14,...) = componentwise addition of (1, 2, 3, 4, 5,...) and A061397: (0, 2, 3, 0, 5, 0, 7,...).

LINKS

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

FORMULA

Triangle read by rows, T(n,k) = 2 if n is prime, 1 otherwise; 1<=k<=n

EXAMPLE

First few rows of the triangle =

1;

2, 2;

2, 2, 2;

1, 1, 1, 1;

2, 2, 2, 2, 2;

1, 1, 1, 1, 1, 1;

2, 2, 2, 2, 2, 2, 2;

...

CROSSREFS

Cf. A061397, A143545.

Sequence in context: A214564 A102675 A177849 * A031346 A335808 A087472

Adjacent sequences:  A143541 A143542 A143543 * A143545 A143546 A143547

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Aug 23 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 May 7 12:38 EDT 2021. Contains 343650 sequences. (Running on oeis4.)