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A178850
Lexicographically earliest infinite sequence such that (a(i)-a(j)) mod (a(k)-a(j)) is nonzero whenever i,j,k are disjoint.
0
1, 3, 6, 10, 20, 32, 112, 184, 232, 268, 364, 508, 2308, 3028, 5332, 8212, 46372, 75892, 106852, 116212, 191812, 222052, 265252, 298372, 315652, 328612, 361012, 401332, 444532, 507172, 635332, 706612, 787252, 943492, 1147252, 1210612, 1270372
OFFSET
1,2
COMMENTS
First infinite picket-fence sequence: a picket fence extended from any pair in the set encounters no other member of the set.
Terms in this sequence gradually become restricted in increasing moduli. From a(7) on, all terms are == 4 (mod 12).
EXAMPLE
From the initial 1,3, no further terms can be odd. After 3,6, no further multiples of 3 are possible. After 1,3,6, an 8 would be legal, except that no further extension of the sequence is then possible.
CROSSREFS
Cf. A178758.
Sequence in context: A058356 A270048 A295719 * A018171 A306357 A365694
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Jon E. Schoenfield, Jun 25 2010
STATUS
approved