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A082190 In the following square array, numbers (not occurring earlier) are entered like this a(1,1),a(1,2),a(2,1),a(3,1),a(2,2),a(1,3),a(1,4),a(2,3),a(3,2),a(4,1),a(5,1),a(4,2),... such that every entry is coprime to its neighbor in all directions. 1 2 7 6 23 10... 3 5 11 19... 4 13 12... 9 17 ... 8... ... e.g. a(2,2) = 5 and its neighbors are 1,2,7,11,12,13,4, and 3 which are co- prime to 5. Sequence contains the sum of the antidiagonals. +0
5
1, 5, 16, 39, 79, 157, 190, 337, 407, 705, 742, 1147, 1235, 1855, 1836, 2879, 2691, 4067, 3752, 5683, 5005, 7687, 6670, 10117, 8595, 12837, 10950, 15737, 13461, 19621 (list; graph; listen)
OFFSET

1,2

EXAMPLE

In the following square array, numbers (not occurring earlier) are entered like this a(1,1),a(1,2),a(2,1),a(3,1),a(2,2),a(1,3),a(1,4),a(2,3),a(3,2),a(4,1),a(5,1),a(4,2),... such that every entry is coprime to its neighbor in all directions.

1 2 7 6 23 10...

3 5 11 19...

4 13 12...

9 17 ...

8...

...

Sequence contains the sum of the antidiagonals.

CROSSREFS

Cf. A082025, A082187, A082188, A082189.

Adjacent sequences: A082187 A082188 A082189 this_sequence A082191 A082192 A082193

Sequence in context: A011932 A131283 A082199 this_sequence A011863 A027085 A099452

KEYWORD

more,nonn,uned

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 07 2003

EXTENSIONS

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 06 2006

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Last modified October 6 16:13 EDT 2008. Contains 144667 sequences.


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