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A296991 Numbers n such that n^2 divides tau(n), where tau(n)=A000594(n) is Ramanujan's tau function. 6
1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 21, 24, 27, 32, 36, 40, 42, 48, 54, 64, 72, 81, 84, 96, 108, 120, 128, 135, 144, 162, 168, 189, 192, 216, 243, 256, 270, 280, 288, 324, 336, 360, 378, 384, 432, 448, 486, 512, 540, 576, 640, 648, 672, 729, 756, 768, 828, 840, 864 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

2^n is a term for n >= 0.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..500

Eric Weisstein's World of Mathematics, Tau Function

MATHEMATICA

fQ[n_] := Mod[RamanujanTau@n, n^2] == 0; Select[Range@875, fQ] (* Robert G. Wilson v, Dec 23 2017 *)

PROG

(PARI) is(n) = Mod(ramanujantau(n), n^2)==0 \\ Felix Fröhlich, Dec 24 2017

CROSSREFS

Cf. A000594, A063938, A296992, A296993.

Sequence in context: A067947 A279542 A053640 * A097755 A301704 A083854

Adjacent sequences:  A296988 A296989 A296990 * A296992 A296993 A296994

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Dec 22 2017

STATUS

approved

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Last modified August 19 04:21 EDT 2019. Contains 326109 sequences. (Running on oeis4.)