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A097023 Numbers n such that the sum of the divisors of 2*n^2 is a square. 7
313, 335, 2612, 2817, 3015, 3820, 23508, 34380, 36647, 38193, 42217, 50281, 64972, 73535, 96404, 103180, 155991, 265364, 325847, 329823, 379953, 397068, 452529, 476545, 584748, 624748, 661815, 668660, 867636, 928620 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..200

EXAMPLE

sigma[2*313^2]=543^2

MATHEMATICA

Select[Range[950000], IntegerQ[Sqrt[DivisorSigma[1, 2#^2]]]&] (* Harvey P. Dale, Jul 10 2012 *)

CROSSREFS

Cf. A008847, A000203, A097024.

Sequence in context: A083972 A045275 A238057 * A159574 A139656 A061323

Adjacent sequences:  A097020 A097021 A097022 * A097024 A097025 A097026

KEYWORD

nonn

AUTHOR

Labos Elemer, Aug 24 2004

EXTENSIONS

Definition clarified by Harvey P. Dale, Jul 10 2012

STATUS

approved

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Last modified August 18 09:47 EDT 2022. Contains 356204 sequences. (Running on oeis4.)