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Search: id:A147790
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| A147790 |
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a(1) = 3, a(n) = Round(a(n-1)*3/2) for n > 1, using round-to-even method. |
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3
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| 3, 4, 6, 9, 14, 21, 32, 48, 72, 108, 162, 243, 364, 546, 819, 1228, 1842, 2763, 4144, 6216, 9324, 13986, 20979, 31468, 47202, 70803, 106204, 159306, 238959, 358438, 537657, 806486, 1209729, 1814594, 2721891, 4082836, 6124254, 9186381, 13779572
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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See Wikipedia link and MathWorld link for different methods of rounding half-integers.
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LINKS
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Wikipedia, Rounding
Eric Weisstein's MathWorld, Nearest Integer Function
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EXAMPLE
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a(2) = Round(3*3/2) = 4; a(3) = Round(4*3/2) = 6; a(4) = Round(6*3/2) = 9.
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MATHEMATICA
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lst={}; s=2; Do[s=Round[s*1.5]; AppendTo[lst, s], {n, 1, 5!}]; lst
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PROGRAM
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(MAGMA) RoundToEven:=function(n); d:=Floor(n); return n-d ne 1/2 select Round(n) else d+(d mod 2); end function; [ n eq 1 select 3 else RoundToEven(Self(n-1)*3/2): n in [1..39] ]; [From Klaus Brockhaus, Nov 17 2008]
(PARI) {RoundToEven(n)=local(d); d=divrem(n, 1); if(d[2]<>1/2, round(n), d[1]+d[1]%2)} {a=2; while(a<10^7, print1(a=RoundToEven(a*3/2), ", "))} [From Klaus Brockhaus, Nov 17 2008]
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CROSSREFS
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Cf. A061418, A147788, A147789.
Sequence in context: A005626 A030712 A025000 this_sequence A048577 A107340 A018830
Adjacent sequences: A147787 A147788 A147789 this_sequence A147791 A147792 A147793
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KEYWORD
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nonn
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AUTHOR
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Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 13 2008
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EXTENSIONS
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Edited by Klaus Brockhaus, Nov 17 2008
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