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 A098955 Numbers with property that the last digit is the length of the number (written in base 10). 3
 1, 12, 22, 32, 42, 52, 62, 72, 82, 92, 103, 113, 123, 133, 143, 153, 163, 173, 183, 193, 203, 213, 223, 233, 243, 253, 263, 273, 283, 293, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 403, 413, 423, 433, 443, 453, 463, 473, 483, 493, 503 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Otherwise said: list of n-digit numbers with n+1 appended, for n=0,1,2,... The sequence is obviously finite, since the largest possible digit and thus maximal possible length of a term is 9. The formula confirms that the last and largest term is a(10^8)=999999999. - M. F. Hasler, Jan 06 2013 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = 10(n-1)+2 = 10n-8 for n=2,...,10, a(n) = 10(n-1)+3 = 10n-7 for n=11,...,100, a(n) = 10(n-1)+4 = 10n-6 for n=101,...,1000, and so on, a(n) = 10(n-1)+k+1 = 10n-(9-k) for 10^(k-1) < n <= 10^k, up to a(n) = 10(n-1)+9 = 10n-1 for n=10^7+1,...,10^8. - M. F. Hasler, Jan 06 2013 MAPLE 1, seq(seq(10*(n-1)+d, n=10^(d-2)+1..10^(d-1)), d=2..4); # Robert Israel, Aug 17 2018 PROG (PARI) A098955(n)=n*10-9+#Str(n-1)-(n==1) \\ M. F. Hasler, Jan 06 2013 (Python) def a(n): s = str(n); return int(s + str(len(s) + int(n != 0))) print([a(n) for n in range(51)]) # Michael S. Branicky, Aug 04 2022 CROSSREFS Sequence in context: A278030 A286094 A348187 * A285470 A124885 A115745 Adjacent sequences: A098952 A098953 A098954 * A098956 A098957 A098958 KEYWORD base,easy,nonn,fini AUTHOR Eric Angelini, Oct 21 2004 STATUS approved

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Last modified July 23 06:44 EDT 2024. Contains 374544 sequences. (Running on oeis4.)