A130279 - OEIS

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A130279

Smallest number having exactly n square divisors.

1, 4, 16, 36, 256, 144, 4096, 576, 1296, 2304, 1048576, 3600, 16777216, 36864, 20736, 14400, 4294967296, 32400, 68719476736, 57600, 331776, 9437184, 17592186044416, 129600, 1679616, 150994944, 810000, 921600, 72057594037927936 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`A046951(a(n)) = n and A046951(m) <> n for m < a(n);` `all terms are smooth squares: if prime(k) is a factor of a(n) then also prime(i) are factors, i<k;` `a(p) = 2^(2(p-1)) for primes p;` `if prime(j) is the greatest prime factor of a(n) then a(2n) = a(n)prime(j+1)^2;` `A001221(a(n)) = A122375(n); A001222(a(n)) = 2A122376(n).`
	LINKS	`Eric Weisstein's World of Mathematics, Smooth Number`
	CROSSREFS	`Sequence in context: A136404 A046952 A081456 * A030158 A054246 A173545` `Adjacent sequences: A130276 A130277 A130278 * A130280 A130281 A130282`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 20 2007`

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Last modified February 16 04:47 EST 2012. Contains 205860 sequences.