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A244733 Semiprimes sp such that sp plus its digit sum is a perfect square. 2

%I #14 Jul 17 2014 22:28:36

%S 38,86,161,614,662,998,1145,1355,1829,2189,2483,4607,5027,5315,6377,

%T 7199,8258,11435,13214,15611,17933,19574,20153,21305,21878,24014,

%U 26867,30599,32738,34199,36077,38387,38777,40778,42422,46211,51509,52874,56618,58541,59987

%N Semiprimes sp such that sp plus its digit sum is a perfect square.

%H K. D. Bajpai, <a href="/A244733/b244733.txt">Table of n, a(n) for n = 1..1150</a>

%e 86 is in the sequence because 86 = 2* 43, which is semiprime. Also, 86 + (8 + 6) = 100 = 10^2.

%e 614 is in the sequence because 614 = 2* 307, which is semiprime. Also, 614 + (6 + 1 + 4) = 625 = 25^2.

%t Select[Range[50000], PrimeOmega[#] == 2 && IntegerQ[Sqrt[# + Apply[Plus, IntegerDigits[#]]]] &]

%Y Cf. A007953, A028839, A048519, A107288, A244863.

%K nonn,base

%O 1,1

%A _K. D. Bajpai_, Jul 12 2014

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Last modified April 24 19:31 EDT 2024. Contains 371962 sequences. (Running on oeis4.)