A089889 - OEIS

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A089889

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

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 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`a(n)=A000196(n)*A089887(n);` `for n>1: a(n) = A089886(n,1).`
	FORMULA	`a(n) = n^(1/2) * 2^(n-n^(1/2)).`
	CROSSREFS	`Cf. A089890.` `Sequence in context: A036146 A036144 A009641 * A054045 A008860 A145114` `Adjacent sequences: A089886 A089887 A089888 * A089890 A089891 A089892`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 13 2003`

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Last modified February 16 10:28 EST 2012. Contains 205904 sequences.