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Numbers containing squares of Pythagorean triples in their divisor set.
0

%I #16 Jul 06 2021 02:38:22

%S 3600,7200,10800,14400,18000,21600,25200,28800,32400,36000,39600,

%T 43200,46800,50400,54000,57600,61200,64800,68400,72000,75600,79200,

%U 82800,86400,90000,93600,97200,100800,104400,108000,111600,115200,118800

%N Numbers containing squares of Pythagorean triples in their divisor set.

%C a(n) = m * (A046083(k)*A046084(k)*A009000(k))^2 for appropriate, not necessarily unique m and k.

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PythagoreanTriple.html">Pythagorean Triple</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F a(n) = n*60^2.

%e 5^2+12^2=13^2: 5^2, 12^2 and 13^2 are divisors of 608400=(13*5*3*2^2)^2, therefore 608400 is a term.

%Y Cf. Pythagorean triples: A046083, A046084, A009000.

%Y Cf. A094519.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Aug 13 2004

%E Name clarified by _Tanya Khovanova_, Jul 05 2021