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%I A245362 #13 Jun 25 2022 12:02:05
%S A245362 51,323,341,422,591,993,998,4227,4265,5129,5534,5921,5937,8049,8657,
%T A245362 8801,9953,32133,32282,32471,32597,32817,34091,34379,36611,36863,
%U A245362 38937,42011,42243,42605,53211,53673,55745,57167,57903,59543,82151,86354,86781,88217,88433
%N A245362 Semiprimes whose reversal + 1 is a square.
%C A245362 Semiprimes in A245361.
%C A245362 Similar sequence for primes at A167217.
%H A245362 K. D. Bajpai, <a href="/A245362/b245362.txt">Table of n, a(n) for n = 1..1054</a>
%e A245362 341 is in the sequence because 341 = 11 * 31, which is semiprime, and reversal(341) + 1 = 143 + 1 = 144 = 12^2.
%e A245362 591 is in the sequence because 591 = 3 * 197, which is semiprime, and reversal(591) + 1 = 195 + 1 = 196 = 14^2.
%t A245362 Select[Range[10^5], PrimeOmega[#] == 2 && IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[#]]] + 1]] &]
%o A245362 (PARI)
%o A245362 revint(n) = eval(concat(Vecrev(Str(n))))
%o A245362 select(n->bigomega(n)==2 && issquare(revint(n)+1), vector(100000, n, n)) \\ _Colin Barker_, Jul 20 2014
%Y A245362 Cf. A000290, A001358, A167217, A245361.
%K A245362 nonn,base
%O A245362 1,1
%A A245362 _K. D. Bajpai_, Jul 18 2014

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