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 A179956 a(n) is the smallest integer that contains a(n-1) but does not begin with a(n-1). 0
 1, 21, 121, 1121, 11121, 111121, 1111121, 11111121, 111111121, 1111111121, 11111111121, 111111111121, 1111111111121, 11111111111121, 111111111111121, 1111111111111121, 11111111111111121, 111111111111111121, 1111111111111111121, 11111111111111111121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA For n > 2, a(n) = 10^(n-1) + a(n-1). - Jon Maiga, Aug 04 2019 EXAMPLE The next term after 1 is 21, because 21 is the lowest integer higher than 1 that contains a 1 but does not start with 1. MATHEMATICA a[1] = 1 a[2] = 21 a[n_] := 10^(n - 1) + a[n - 1] Array[a, 20] (* Jon Maiga, Aug 04 2019 *) CROSSREFS Sequence in context: A200888 A179441 A164785 * A117388 A053052 A243882 Adjacent sequences:  A179953 A179954 A179955 * A179957 A179958 A179959 KEYWORD easy,base,nonn AUTHOR Dominick Cancilla, Aug 03 2010 EXTENSIONS Definition corrected and more terms added by Jon Maiga, Aug 04 2019 STATUS approved

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Last modified June 18 03:46 EDT 2021. Contains 345098 sequences. (Running on oeis4.)