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A094147
Numbers that can be written as sum of squares of two divisors.
2
2, 8, 18, 20, 32, 50, 72, 80, 90, 98, 128, 162, 180, 200, 242, 272, 288, 320, 338, 360, 392, 450, 468, 500, 512, 578, 648, 650, 720, 722, 800, 810, 882, 968, 980, 1058, 1088, 1152, 1250, 1280, 1332, 1352, 1440, 1458, 1568, 1620, 1682, 1800, 1872
OFFSET
1,1
LINKS
EXAMPLE
6 and 12 are divisors of 180 and 6^2 + 12^2 = 36 + 144 = 180, therefore 180 is a term.
MATHEMATICA
aQ[n_] := AnyTrue[n - Divisors[n]^2, IntegerQ[(s = Sqrt[#])] && s>0 && Divisible[n, s] &]; Select[Range[2, 1872], aQ] (* Amiram Eldar, Sep 02 2019 *)
CROSSREFS
Subsequence of A000404.
A001105 is a subsequence.
Sequence in context: A228615 A267823 A063664 * A117612 A320662 A171613
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 01 2004
STATUS
approved