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A217657
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Delete the initial digit in decimal representation of n.
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12
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,13
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COMMENTS
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When n - a(n)*10^[log_10 n] >= 10^[(log_10 n) - 1], where [] denotes floor, or when n < 100 and 10|n, n is the concatenation of A000030(n) and a(n) - corrected by Glen Whitney, Jul 01 2022
a(110) = 10 is the first term > 9. The sequence consists of 10 repetitions of 0 (n = 0..9), then 9 repetitions of {0, ..., 9} (n = 10..99), then 9 repetitions of {0, ..., 99} (n = 100..999), and so on. - M. F. Hasler, Oct 18 2017
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LINKS
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FORMULA
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a(n) = 0 if n <= 9, otherwise 10*a(floor(n/10)) + n mod 10.
a(n) = n mod 10^floor(log_10(n)), a(0) = 0. - M. F. Hasler, Oct 18 2017
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MATHEMATICA
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PROG
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(Haskell)
a217657 n | n <= 9 = 0
| otherwise = 10 * a217657 n' + m where (n', m) = divMod n 10
(PARI) apply( A217657(n)=n%10^logint(n+!n, 10), [0..199]) \\ M. F. Hasler, Oct 18 2017, edited Dec 22 2019
(Python)
def a(n): return 0 if n < 10 else int(str(n)[1:])
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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Data extended to include the first terms larger than 9, by M. F. Hasler, Dec 22 2019
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STATUS
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approved
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