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 A018870 9^a(n) is smallest power of 9 beginning with n. 3
 0, 12, 9, 7, 5, 4, 3, 2, 1, 21, 42, 20, 19, 40, 18, 17, 60, 16, 59, 15, 80, 14, 101, 57, 13, 78, 34, 12, 77, 33, 11, 98, 54, 10, 119, 75, 53, 9, 118, 96, 52, 30, 8, 95, 73, 51, 7, 138, 94, 72, 50, 28, 6, 115, 93, 71, 49, 27, 5, 114, 92, 70, 48, 26, 4, 135, 113, 91, 69, 47, 25, 3, 134 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS D. Mondot, Table of n, a(n) for n = 1..32699 EXAMPLE a(2) = 12 since 9^12 = 282429536481 is the smallest power of 9 that begins with 2. PROG (Python) def a(n): s, k = str(n), 0 while not str(9**k).startswith(s): k += 1 return k print([a(n) for n in range(1, 74)]) # Michael S. Branicky, Dec 09 2021 CROSSREFS Cf. A001019, A018869. Sequence in context: A299515 A326927 A338289 * A327470 A068614 A163920 Adjacent sequences: A018867 A018868 A018869 * A018871 A018872 A018873 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified March 30 02:00 EDT 2023. Contains 361599 sequences. (Running on oeis4.)