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 A327270 The minimum number such that the concatenation of the absolute values of differences between adjacent digits of a(n) is n. Values of n which have no such a(n) are given as -1. 0
 10, 13, 14, 15, 16, 17, 18, 19, 90, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 133, 132, 131, 130, 137, 138, 139, 207, 208, 209, 144, 143, 142, 141, 140, 149, 306, 307, 308, 309, 155, 154, 153, 152, 151, 150, 260, 370, 408, 409, 166, 165, 164, 163, 162, 161, 160, 270 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence gives the minimum value such that the concatenation of the absolute value of the differences between its adjacent digits give n. Some values of n have no ancestor, see A271639. These are given the value -1 in this sequence. LINKS EXAMPLE a(1) = 10 as |1 - 0| = 1, and 10 is the smallest such number. a(9) = 90 as |9 - 0| = 9, and 90 is the smallest such number a(10) = 100 as |1 - 0| = 1, and |0 - 0| = 0, giving a concatenation of 10. 100 is the smallest such number. a(48) = 408 as |4 - 0| = 4 and |0 - 8| = 8, giving a concatenation of 48. 408 is the smallest such number. MATHEMATICA max = 60; seq = Table[-1, {max}]; count = 0; n = 1; While[count < max && n <= 10^(1 + Ceiling[Log10[max]]), index = FromDigits @ Abs @ Differences @ IntegerDigits[n]; If[index <= max && seq[[index]] < 0, count++; seq[[index]] = n]; n++]; seq (* Amiram Eldar, Nov 29 2019 *) CROSSREFS Cf. A271639, A040115. Sequence in context: A131365 A241144 A102362 * A070837 A188643 A087140 Adjacent sequences:  A327267 A327268 A327269 * A327271 A327272 A327273 KEYWORD nonn,base AUTHOR Scott R. Shannon, Nov 29 2019 STATUS approved

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Last modified January 24 10:24 EST 2020. Contains 331193 sequences. (Running on oeis4.)