A089889 - OEIS

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A089889

Number of subsets of {1,.., n} containing exactly one square.

3

1, 2, 4, 8, 16, 32, 64, 128, 192, 384, 768, 1536, 3072, 6144, 12288, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 5242880, 10485760, 20971520, 41943040, 83886080, 167772160, 335544320, 671088640, 1342177280

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OFFSET

1,2

COMMENTS

a(n)=A000196(n)*A089887(n);

for n>1: a(n) = A089886(n,1).

LINKS

Table of n, a(n) for n=1..33.

FORMULA

a(n) = n^(1/2) * 2^(n-n^(1/2)).

CROSSREFS

Sequence in context: A327368 A286660 A009641 * A297526 A229617 A306316

Adjacent sequences: A089886 A089887 A089888 * A089890 A089891 A089892

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 13 2003

STATUS

approved