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A054017 Chowla's function of n modulo n is a square (excluding 0's). 3
14, 20, 39, 40, 46, 55, 80, 94, 100, 104, 117, 130, 155, 158, 183, 190, 200, 203, 291, 292, 295, 299, 320, 323, 334, 416, 430, 446, 464, 475, 488, 530, 539, 549, 567, 579, 583, 638, 650, 695, 718, 799, 873, 878, 890, 943, 955, 959, 964, 979, 1030, 1118 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Chowla's function (A048050) = sum of divisors of n except 1 and n.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

aQ[n_] := (c = DivisorSigma[1, n] - n - 1) > 0 && IntegerQ @ Sqrt @ Mod[c, n]; Select[Range[1000], aQ] (* Amiram Eldar, Aug 28 2019 *)

CROSSREFS

Cf. A048050, A054013, A054018.

Sequence in context: A108874 A063848 A110968 * A129216 A259536 A067796

Adjacent sequences:  A054014 A054015 A054016 * A054018 A054019 A054020

KEYWORD

nonn

AUTHOR

Asher Auel (asher.auel(AT)reed.edu), Jan 19 2000

STATUS

approved

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Last modified August 5 10:01 EDT 2021. Contains 346464 sequences. (Running on oeis4.)