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A069067 Numbers n such that n*tau(n) is a perfect square. 1
1, 2, 36, 100, 108, 128, 196, 225, 256, 288, 441, 450, 484, 600, 675, 676, 800, 864, 882, 1089, 1156, 1176, 1225, 1296, 1323, 1350, 1444, 1521, 1568, 1944, 2000, 2116, 2178, 2450, 2601, 2646, 2904, 3025, 3042, 3240, 3249, 3267, 3364, 3844, 3872, 4056 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[4200], IntegerQ[Sqrt[# DivisorSigma[0, #]]]&] (* Harvey P. Dale, Apr 21 2019 *)

CROSSREFS

Sequence in context: A328963 A081310 A187298 * A278930 A258356 A145450

Adjacent sequences:  A069064 A069065 A069066 * A069068 A069069 A069070

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 05 2002

STATUS

approved

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Last modified February 18 09:39 EST 2020. Contains 332011 sequences. (Running on oeis4.)