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Search: id:A112884
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| A112884 |
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Number of bits required to represent binomial(2^n, 2^(n-1)). |
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+0
1
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| 2, 3, 7, 14, 30, 61, 125, 252, 508, 1019, 2043, 4090, 8186, 16377, 32761, 65528, 131064, 262135, 524279, 1048566, 2097142, 4194293, 8388597
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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Appears to be equal to 2^n - floor(n / 2)
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EXAMPLE
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a(2) = 3 because binomial(2^2, 2^1) in binary = 110
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PROGRAM
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PHP code: $LastFact = gmp_init('1'); for ($i = 2; $i !== 65536; $i *= 2) { $Fact = gmp_fact($i); $Result = gmp_div_q($Fact, gmp_pow($OldFact, 2)); $LastFact = $Fact; echo gmp_strval($Result, 2).'<br>'; }
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CROSSREFS
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a(n) represents the size of A037293 in binary - see also the central binomial coefficients: A001405.
Sequence in context: A034065 A034075 A019595 this_sequence A103421 A151530 A000642
Adjacent sequences: A112881 A112882 A112883 this_sequence A112885 A112886 A112887
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KEYWORD
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easy,nonn
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AUTHOR
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Matt Erbst (matt(AT)erbst.org), Oct 04 2005
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