OFFSET
1,2
LINKS
EXAMPLE
If viewed as a regular triangle:
1;
3, 2;
6, 4, 5;
10, 8, 7, 9;
15, 13, 11, 12, 14;
21, 19, 17, 16, 18, 20;
28, 26, 24, 22, 23, 25, 27;
36, 34, 32, 30, 29, 31, 33, 35;
45, 43, 41, 39, 37, 38, 40, 42, 44;
55, 53, 51, 49, 47, 46, 48, 50, 52, 54;
66, 64, 62, 60, 58, 56, 57, 59, 61, 63, 65;
78, 76, 74, 72, 70, 68...
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
N. J. A. Sloane, Oct 20 2001
EXTENSIONS
More terms from David Wasserman, Aug 14 2002
STATUS
approved