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A082191
In a square array, positive integers are entered as follows. Start with a(1, 1)=1. Then enter numbers in this order: 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 the smallest not yet used and such that every entry greater than 1 has a common divisor with its neighbors (in all directions) which are greater than 1.
4
1, 2, 4, 6, 8, 10, 5, 20, 12, 3, 9, 15, 18, 30, 25, 35, 40, 14, 21, 24, 27, 33, 36, 39, 42, 16, 50, 28, 7, 56, 22, 26, 48, 45, 51, 54, 32, 60, 57, 63, 66, 34, 38, 70, 49, 77, 84, 44, 46, 52, 72, 69, 75, 78, 58, 29, 116, 80, 90, 81, 96, 62, 64, 68, 98, 88, 11, 110, 74, 76, 82, 86
OFFSET
1,2
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 07 2003
EXTENSIONS
Corrected and extended by Matthew Conroy, Sep 03 2007
STATUS
approved