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A176471 Duplicate of A136404, 1
1, 4, 16, 36, 144, 576, 900, 3600, 14400, 32400, 44100, 129600, 176400, 705600, 1587600, 2822400, 6350400, 21344400, 57153600, 85377600, 192099600, 341510400, 768398400, 3073593600, 6915585600, 12294374400, 14428814400, 32464832400, 57715257600, 129859329600 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Same as A136404. - Georg Fischer, Oct 12 2018

Previous name was: Highly composite square numbers for which the number of divisors increases to a record.

LINKS

Table of n, a(n) for n=1..30.

MATHEMATICA

With[{sqs=Range[10000]^2}, Union[Flatten[Table[Select[sqs, DivisorSigma[ 0, #]>n&, 1], {n, 500}]]]] (* Harvey P. Dale, Apr 28 2012 *)

t = {1}; sig = {1}; n = 1; Do[While[n++; d = DivisorSigma[0, n^2]; d <= sig[[-1]]]; AppendTo[sig, d]; AppendTo[t, n^2], {30}]; t (* T. D. Noe, Apr 30 2012 *)

CROSSREFS

Cf. A126098 (square root of these terms).

Cf. A136404. - Georg Fischer, Oct 12 2018

Sequence in context: A181795 A277285 A136404 * A046952 A318278 A293708

Adjacent sequences:  A176468 A176469 A176470 * A176472 A176473 A176474

KEYWORD

dead

AUTHOR

Ethan Ward (etkewa(AT)gmail.com), Apr 18 2010

EXTENSIONS

Corrected and extended by Harvey P. Dale, Apr 28 2012

STATUS

approved

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Last modified April 22 16:32 EDT 2021. Contains 343177 sequences. (Running on oeis4.)