

A214177


Sum of the 4 nearest neighbors of n in a spiral with positive integers.


6



20, 24, 32, 24, 44, 32, 56, 40, 44, 72, 52, 56, 88, 64, 68, 72, 108, 80, 84, 88, 128, 96, 100, 104, 108, 152, 116, 120, 124, 128, 176, 136, 140, 144, 148, 152, 204, 160, 164, 168, 172, 176, 232, 184, 188, 192, 196, 200, 204, 264, 212, 216, 220, 224, 228, 232, 296
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OFFSET

1,1


COMMENTS

Nearby numbers on diagonals are not counted as neighbors for this sequence.


LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..5202
Rémy Sigrist, PARI program for A214177


EXAMPLE

Spiral begins:
.
49 262728293031
  
48 25 10111213 32
    
47 24 9 23 14 33
      
46 23 8 1 4 15 34
     
45 22 765 16 35
   
44 2120191817 36
 
43424140393837
.
The four nearest neighbors of 2 are 1, 3, 9, 11. Their sum is a(2) = 24.


PROG

(PARI) See Links section.


CROSSREFS

Cf. A137928, A137930, A137931, A002061, A114254.
Cf. A214176 (sum of the 8 nearest neighbors).
Sequence in context: A109131 A171696 A060461 * A044996 A347190 A263016
Adjacent sequences: A214174 A214175 A214176 * A214178 A214179 A214180


KEYWORD

nonn,easy


AUTHOR

Alex Ratushnyak, Jul 06 2012


STATUS

approved



