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Search: id:A140057
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| A140057 |
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Numbers such that each decimal digit d (for all d in the range 1 <= d <= 9) occurs only in runs of length exactly d. |
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+0
2
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| 1, 22, 122, 221, 333, 1221, 1333, 3331, 4444, 13331, 14444, 22122, 22333, 33322, 44441, 55555, 122122, 122333, 133322, 144441, 155555, 221221, 221333, 223331, 224444, 333122, 333221, 444422, 555551, 666666, 1221221, 1221333, 1223331
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Number of terms less than 10^k: 1, 2, 5, 9, 16, 30, 53, 92, 163, 286, 497, 869, 1516, 2639, 4606, 8032, 13993, ..., . - Robert G. Wilson v.
Number of terms of k digits: 1, 1, 3, 4, 7, 14, 23, 39, 71, 123, 211, 372, 647, 1123, 1967, 3426, 5961, ..., ; not the same as A003242. - Robert G. Wilson v.
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LINKS
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Robert G. Wilson v, Table of n, a(n) for n = 1..8032
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MATHEMATICA
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(* first do *) Needs["Combinatorica`"] (* then *) f[n_] := Block[{ pa=Partitions@ n, len = PartitionsP@ n, s, lst, lmt}, s = Select[Range@len, pa[[ #, 1]] < 10 &]; lst=Take[pa, {s[[1]], -1}]; lst = Flatten[ DistinctPermutations /@ lst, 1]; lmt = Length@ lst; While[lmt != 0, If[ Split[lst[[lmt]]] != Partition[lst[[lmt]], 1], lst = Delete[lst, lmt]]; lmt-- ]; Sort@ (FromDigits /@ Flatten /@ (lst /. {x_Integer -> Table[x, {x}]}))] (* Robert G. Wilson v, (rgwv(AT)rgwv.com), May 25 2008 *)
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CROSSREFS
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Sequence in context: A108571 A105776 A044354 this_sequence A044735 A061597 A039439
Adjacent sequences: A140054 A140055 A140056 this_sequence A140058 A140059 A140060
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KEYWORD
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base,easy,nonn
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AUTHOR
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Rick L. Shepherd (rshepherd2(AT)hotmail.com), May 03 2008
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EXTENSIONS
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Definition expanded by N. J. A. Sloane (njas(AT)research.att.com), May 20 2008
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