

A214231


Sum of the four nearest neighbors of n in a right triangular type1 spiral with positive integers.


2



19, 35, 33, 52, 32, 33, 58, 41, 45, 58, 98, 75, 70, 74, 90, 127, 89, 81, 85, 89, 93, 136, 101, 105, 109, 113, 117, 139, 197, 156, 142, 146, 150, 154, 158, 183, 238, 182, 165, 169, 173, 177, 181, 185, 189, 250, 197, 201, 205, 209, 213, 217, 221, 225, 256, 332
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Nearby numbers on diagonals are not counted as neighbors for this sequence.
Right triangular type1 spiral implements the sequence Up, Rightdown, Left.


LINKS



EXAMPLE

Right triangular spiral begins:
56
55 57
54 29 58
53 28 30 59
52 27 11 31 60
51 26 10 12 32 61
50 25 9 2 13 33 62
49 24 8 1 3 14 34 63
48 23 7 6 5 4 15 35 64
47 22 21 20 19 18 17 16 36 65
46 45 44 43 42 41 40 39 38 37 66
78 77 76 75 74 73 72 71 70 69 68 67
The four nearest neighbors of 3 are 1, 13, 14, 5. Their sum is a(3)=33.


CROSSREFS

Cf. A214230  sum of the 8 nearest neighbors, Python program.


KEYWORD

nonn,easy


AUTHOR



STATUS

approved



