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%I #10 Nov 10 2022 12:36:03
%S 51,65,87,111,129,146,209,249,278,291,305,335,377,407,447,485,489,497,
%T 629,681,699,749,767,785,917,939,951,989,1007,1018,1037,1115,1177,
%U 1191,1257,1397,1457,1469,1497,1509,1546,1565,1594,1707,1731,1757,1799,1945,1977
%N Lesser of two consecutive semiprimes whose sum and difference are also semiprimes.
%C Intersection of A272306 and A272307.
%H Robert Israel, <a href="/A335346/b335346.txt">Table of n, a(n) for n = 1..10000</a>
%e 51 = A272306(8) = A272307(3), 65 = A272306(10) = A272307(5).
%p b:= 4:
%p Res:= NULL: count:= 0:
%p while count < 100 do
%p a:= b;
%p for k from b+1 do if numtheory:-bigomega(k) = 2 then b:= k; break fi od:
%p if numtheory:-bigomega(b-a) = 2 and numtheory:-bigomega(b+a) = 2 then
%p count:= count+1; Res:= Res, a;
%p fi
%p od:
%p Res; # _Robert Israel_, Nov 10 2022
%o (PARI) psp=4;for(k=6,2000,if(bigomega(k)==2,if(bigomega(k-psp)==2,if(bigomega(k+psp)==2,print1(psp,", ")));psp=k)) \\ _Hugo Pfoertner_, Jun 03 2020
%Y Cf. A001358, A272306, A272307, A272308, A272309.
%K nonn
%O 1,1
%A _Zak Seidov_, Jun 02 2020
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