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Search: id:A082187
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| A082187 |
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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 first row. |
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5
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| 1, 2, 7, 6, 23, 10, 21, 20, 33, 28, 51, 44, 87, 56, 117, 80, 153, 100, 201, 110
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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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 first row.
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.
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CROSSREFS
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Cf. A082025, A082188, A082189, A082190.
Sequence in context: A089417 A082017 A072985 this_sequence A021365 A021787 A011052
Adjacent sequences: A082184 A082185 A082186 this_sequence A082188 A082189 A082190
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KEYWORD
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more,nonn,uned
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 07 2003
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 06 2006
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