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Search: id:A056189
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A056189 2^n - A056188(n). +0
2
1, 2, 2, 8, 2, 52, 2, 128, 170, 764, 2, 2488, 2, 11624, 16928, 32768, 2, 181324, 2, 555296, 931610, 2802584, 2, 11007664, 6643782, 43955032, 44739242, 136585808, 2, 720895864, 2, 2147483648, 3250384970, 10923540812, 11517062218 (list; graph; listen)
OFFSET

1,2

FORMULA

a(n)=2^n-Sum{binomial[n, k]; k>0, GCD[n, k]=1}

EXAMPLE

a(n)=2 for primes; n=6, a(6)=52 because the sum of coefficients is restricted only to k=1,5 so a(6)=64-6-6.

CROSSREFS

Cf. A056045, A056188.

Sequence in context: A088560 A086328 A095997 this_sequence A121860 A021442 A093731

Adjacent sequences: A056186 A056187 A056188 this_sequence A056190 A056191 A056192

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Aug 02 2000

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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