OFFSET
1,4
COMMENTS
This is the square spiral analogy of Pascal's triangle thought of as a table read by antidiagonals.
LINKS
Peter Kagey, Table of n, a(n) for n = 1..10000
Peter Kagey, Bitmap illustrating the parity of the first 2^20=1048576 terms. (Even and odd numbers are represented with black and white pixels respectively.)
EXAMPLE
Spiral begins:
111--99--87--77--69--62
|
12--12--10---8---7 62
| | |
14 2---2---1 7 55
| | | | |
17 3 1---1 6 48
| | | |
20 3---4---5---5 42
| |
20--23--27--32--37--37
a(15) = 10 = 8 + 2, the sum of the cells immediately to the right and below. The term to the left is not included in the sum because it has not yet occurred in the spiral.
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
Alec Jones and Peter Kagey, May 09 2020
STATUS
approved