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 A110400 a(1) = 1, a(2) = 21; for n>2, a(n) is the least number whose neighboring digit difference forms a(n-1) such that a(n+1) also exists. 0
 1, 21, 132, 1031, 10032, 100031, 1000032, 10000031, 100000032, 1000000031, 10000000032, 100000000031, 1000000000032, 10000000000031, 100000000000032, 1000000000000031, 10000000000000032, 100000000000000031 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(2) = 21 (chosen) and not 10 so that the sequence extends nontrivially. A040115(a(n+1)) = a(n). - David Wasserman, Oct 02 2005 LINKS EXAMPLE After 8421 two possible candidates are 91532 and 91576 but there is no number with digit difference 91576 hence the next term is 91532. 1031 is followed by 10032 because the absolute differences between the numbers 1, 0, 0, 3, 2 are 1, 0, 3, 1. CROSSREFS Cf. A011557. Sequence in context: A228283 A157624 A008384 * A308348 A089369 A328861 Adjacent sequences:  A110397 A110398 A110399 * A110401 A110402 A110403 KEYWORD base,easy,nonn AUTHOR Amarnath Murthy, Jul 29 2005 EXTENSIONS Corrected and extended by David Wasserman, Oct 02 2005 STATUS approved

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Last modified November 30 16:23 EST 2021. Contains 349423 sequences. (Running on oeis4.)