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A328075
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Numbers such that the absolute values of the differences between any pair of digits are distinct.
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1
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 103, 104, 105, 106, 107, 108, 109, 124, 125, 126, 127, 128
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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More than the usual number of terms are shown in order to distinguish this from neighboring sequences.
The definition as it stands would also include single-digit numbers. The nontrivial terms are those with more than 2 digits. - M. F. Hasler, Oct 08 2019
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REFERENCES
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Eric Angelini, Posting to Sequence Fans Mailing List, Oct 07 2019.
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LINKS
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EXAMPLE
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The 2-digit absolute differences of 1862 are 7,5,1,2,6,4, all different, so 1862 is a term (and also the number of terms).
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PROG
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(PARI) select( is(n)={n<99||#Set(abs(concat(vector(-1+#n=digits(n), k, n[1..k]-vector(k, i, 1)*n[k+1]))))*2==#n*(#n-1)}, [1..9999]) \\ M. F. Hasler, Oct 08 2019
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CROSSREFS
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KEYWORD
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nonn,base,fini
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AUTHOR
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STATUS
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approved
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