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A274577 Numbers n such that n is the sum of two nonzero squares while A006530(n) is not. 0
18, 72, 98, 162, 242, 245, 288, 392, 490, 605, 648, 722, 882, 968, 980, 1058, 1152, 1210, 1225, 1458, 1568, 1805, 1922, 1960, 2178, 2205, 2420, 2450, 2592, 2645, 2888, 3025, 3528, 3610, 3698, 3872, 3920, 4232, 4410, 4418, 4608, 4693, 4802, 4805, 4840, 4900, 5290 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

245 is a term because 245 = 5*7^2 = 7^2 + 14^2 and 7 is not the sum of two nonzero squares.

1764 is not a term because 1764 = 2^2*3^2*7^2.

MATHEMATICA

nR[n_]:=(SquaresR[2, n] + Plus@@Pick[{-4, 4}, IntegerQ/@ Sqrt[{n, n/2}]])/8; Select[ Range[10^4], nR[#] > 0 && Mod[FactorInteger[#][[-1, 1]], 4] == 3 &] (* Giovanni Resta, Jun 29 2016 *)

CROSSREFS

Cf. A000404, A006530.

Sequence in context: A088490 A257693 A231328 * A195321 A069058 A262000

Adjacent sequences:  A274574 A274575 A274576 * A274578 A274579 A274580

KEYWORD

nonn,easy

AUTHOR

Altug Alkan, Jun 29 2016

STATUS

approved

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Last modified January 28 00:30 EST 2020. Contains 331303 sequences. (Running on oeis4.)