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A264646
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A simple self-describing sequence S: n concatenated with the n-th digit of S.
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6
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11, 21, 32, 41, 53, 62, 74, 81, 95, 103, 116, 122, 137, 144, 158, 161, 179, 185, 191, 200, 213, 221, 231, 246, 251, 262, 272, 281, 293, 307, 311, 324, 334, 341, 355, 368, 371, 386, 391, 401, 417, 429, 431, 448, 455, 461, 479, 481, 492, 500, 510, 522, 531
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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Although A003602 and this sequence initially agree in their digit-streams, they differ after 48 digits. - N. J. A. Sloane, Nov 20 2015
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LINKS
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EXAMPLE
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. n | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14
. ----+----+---+---+---+---+---+---+---+---+-----+-----+-----+-----+-----
. a(n)| 11 21 32 41 53 62 74 81 95 103 116 122 137 144
. digs| 1 1 2 1 3 2 4 1 5 3 6 2 7 4 8 1 9 5 1 0 3 1 1 6 1 2 2 1 3 7 1 4 4 .
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PROG
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(Haskell)
import Data.List (genericIndex)
a264646 n = a264646_list !! (n-1)
a264646_list = 11 : f 2 [0, 1, 1] where
f x digs = (foldl (\v d -> 10 * v + d) 0 ys) : f (x + 1) (digs ++ ys)
where ys = map (read . return) (show x) ++ [genericIndex digs x]
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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