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Search: id:A105391
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| A105391 |
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Numbers m such that there are an equal number of numbers <= m that are contained and that are not contained in the concatenation of terms <= m in A048991. |
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+0 3
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| 740, 1260, 1262, 5230, 15804, 15814, 15816, 36294, 194876, 213868
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A105390(a(n)) = a(n)/2.
There are no other terms <= 600000. The plots in a105390.gif strongly suggest that the sequence is complete. - Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 15 2007
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LINKS
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Nick Hobson, Python program for this sequence
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EXAMPLE
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A105390(n) < n/2 for n < a(1)=740;
A105390(n) > n/2 for n with 740 < n < a(2)=1260;
A105390(1261)=631, A105390(a(3))=A105390(1262)=631;
A105390(n) < n/2 for n with 1262 < n < a(4)=5230;
A105390(n) > n/2 for n with 5230 < n < a(5)=15804;
A105390(n) < n/2 for n with 15804 < n < a(6)=15814;
A105390(15815)=7908, A105390(a(7))=A105390(15816)=7909;
A105390(n) < n/2 for n with 15816 < n < a(8)=36294;
A105390(n) > n/2 for n with 36294 < n < a(9)=194876; etc.
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PROGRAM
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(JBASIC) From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 15 2007
s$ = "" : c = 0 : d = 0
FOR n = 1 TO 40000
sn$ = str$(n)
IF instr(s$, sn$) > 0 THEN d = d+1 ELSE c = c+1 : s$ = s$ + sn$
IF c = d THEN print n ; ", " ;
NEXT
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CROSSREFS
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Cf. A048991, A048992, A105390, A131981, A131982 (numbers n such that A131981(n) = n/2).
Adjacent sequences: A105388 A105389 A105390 this_sequence A105392 A105393 A105394
Sequence in context: A066404 A066402 A119264 this_sequence A044984 A119595 A000521
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KEYWORD
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nonn,base,more
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 04 2005
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