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A094780
Let 2^k = smallest power of 2 >= binomial(2n,n); a(n) = 2^k - binomial(2n,n).
2
0, 0, 2, 12, 58, 4, 100, 664, 3514, 16916, 77388, 343144, 1490148, 6376616, 26992264, 113317936, 472661434, 1961361076, 8104733884, 33374212936, 137031378124, 11497939448, 94924291832, 562662294608, 2936768405732, 14326881917576, 67031420473208, 304860388037136
OFFSET
0,3
COMMENTS
Suggested by reading the Knuth article.
REFERENCES
D. E. Knuth, Efficient balanced codes, IEEE Trans. Inform. Theory, 32 (No. 1, 1986), 51-53.
EXAMPLE
C(30,15) = 155117520; 2^28 = 268435456; difference is 113317936.
k = 0, 1, 3, 5, 7, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, ... - R. J. Mathar, Nov 15 2019
MAPLE
A094780 := proc(n)
local cb, k ;
cb := binomial(2*n, n) ;
k := ceil(log[2](cb)) ;
2^k-cb ;
end proc:
seq(A094780(n), n=0..10); # R. J. Mathar, Nov 15 2019
CROSSREFS
Sequence in context: A067125 A177782 A005038 * A268594 A100103 A281028
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 10 2004
STATUS
approved