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 A236750 Positive integers k such that k^3 divided by the digital sum of k is a square. 4

%I

%S 1,2,3,4,5,6,7,8,9,12,24,36,48,81,100,144,150,192,196,200,225,242,288,

%T 300,320,324,375,400,441,484,500,512,600,640,648,700,704,735,800,832,

%U 882,900,960,1014,1088,1200,1250,1452,1458,1521,1815,2023,2025,2028

%N Positive integers k such that k^3 divided by the digital sum of k is a square.

%C The sequence is infinite since if m = 10^(2*j) then m^3 / digitsum(m) = m^(6*k). - _Marius A. Burtea_, Dec 21 2018

%H Colin Barker, <a href="/A236750/b236750.txt">Table of n, a(n) for n = 1..1000</a>

%e 192 is in the sequence because the digital sum of 192 is 12, and 192^3/12 = 589824 = 768^2.

%o (PARI)

%o s=[]; for(n=1, 5000, d=sumdigits(n); if(n^3%d==0 && issquare(n^3\d), s=concat(s, n))); s

%o (Magma) [n: n in [1..1500] | IsIntegral((n^3)/(&+Intseq(n))) and IsSquare((n^3)/(&+Intseq(n)))]; // _Marius A. Burtea_, Dec 21 2018

%Y Cf. A001102, A007953, A236748, A236749, A236751.

%K nonn,base

%O 1,2

%A _Colin Barker_, Jan 30 2014

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Last modified April 2 02:09 EDT 2023. Contains 361723 sequences. (Running on oeis4.)