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A068657
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Successive left concatenation of floor(k/2) beginning with n until we reach 1.
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1
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1, 21, 31, 421, 521, 631, 731, 8421, 9421, 10521, 11521, 12631, 13631, 14731, 15731, 168421, 178421, 189421, 199421, 2010521, 2110521, 2211521, 2311521, 2412631, 2512631, 2613631, 2713631, 2814731, 2914731, 3015731, 3115731, 32168421
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Every a(j) will divide some a(k), j<k. - Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 02 2002
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EXAMPLE
| a(21) is constructed by starting with n, 21, then successively Int(21) = 10, Int(10) = 5, Int(5) = 2, Int(2) = 1, which is the end of the process of the halving. Now concatenate the results beginning with n: 21, 10, 5, 2, 1, which results in the number 2110521.
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MAPLE
| for m from 1 to 100 do a := m; n := m; while(n>1) do n := floor(n/2); if(n=1) then a := 10*a+1: else a := a*10^(ceil( log(n)/log(10)-0.000001) )+n:end if:end do:b[m] := a:end do:seq(b[i], i=1..100);
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MATHEMATICA
| f[n_] := Floor[n/2]; Table[ ToExpression[ StringJoin[ ToString /@ Drop[ FixedPointList[f, n], -2]]], {n, 1, 35}]
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CROSSREFS
| Sequence in context: A106324 A032013 A176558 * A068671 A166668 A019423
Adjacent sequences: A068654 A068655 A068656 * A068658 A068659 A068660
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KEYWORD
| base,easy,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 28 2002
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EXTENSIONS
| More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 26 2002. Corrected by Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 02 2002
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