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A338855
Concatenating all successive absolute differences between two successive digits of a(n) produce a subchain of a(n).
3
10, 12, 20, 21, 24, 30, 36, 40, 42, 48, 50, 60, 63, 70, 80, 84, 90, 100, 120, 124, 200, 240, 248, 300, 360, 400, 421, 480, 500, 600, 700, 800, 842, 900, 1000, 1200, 1240, 1248, 2000, 2400, 2480, 3000, 3600, 4000, 4800, 5000, 6000, 7000, 8000, 8421, 9000, 10000, 12000, 12400, 12480, 20000, 24000, 24800, 30000
OFFSET
1,1
COMMENTS
This is the lexicographically earliest sequence of distinct positive terms with this property.
MAPLE
a(1) = 10 is in the sequence because the absolute difference between 1 and 0 is 1, and 1 is a subchain of 10;
a(2) = 12 is in the sequence because the absolute difference between 1 and 2 is 1, and 1 is a subchain of 12;
a(3) = 20 is in the sequence because the absolute difference between 2 and 0 is 2, and 2 is a subchain of 20;
...
a(20) = 124; the absolute difference between 1 and 2 is 1; the absolute difference between 2 and 4 is 2; concatenating those differences produce 12 and 12 is a subchain of 124; etc.
CROSSREFS
Cf. A338640 [the concatenation produces a divisor of a(n)], A338641 [the starting numbers have no duplicated digits and the concatenation is a divisor of a(n)].
Sequence in context: A129845 A075492 A225742 * A221638 A358998 A085772
KEYWORD
base,nonn
AUTHOR
Eric Angelini, Nov 12 2020
STATUS
approved