OFFSET
1,1
COMMENTS
All entries are multiples of 3.
EXAMPLE
If we keep the association with lines in A120070, this triangle here that keeps only each third element starts:
3;
./.;
15;
24,9;
27;
48,33;
63,48,15;
72,45;
99,84,51;
120,105,72,21;
135,108,63;
168,153,120,69;
195,180,147,96,27;
216,189,144,81;
255,240,207,156,87;
288,273,240,189,120,33;
315,288,243,180,99;
360,345,312,261,192,105;
399,384,351,300,231,144,39;
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Paul Curtz, Sep 28 2008
STATUS
approved