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%I #20 Jan 18 2021 02:40:28
%S 4,10,22,25,34,46,55,62,82,85,94,115,118,121,134,146,155,166,187,194,
%T 205,206,218,235,253,254,274,289,295,298,314,334,335,341,358,365,382,
%U 391,394,415,422,451,454,466,482,485,514,515,517,527,529,538,545,554
%N Numbers of the form prime(x) * prime(y) where x and y are both odd.
%F Numbers m such that A001222(m) = A195017(m) = 2. - _Peter Munn_, Jan 17 2021
%e The sequence of terms together with their prime indices begins:
%e 4: {1,1} 146: {1,21} 314: {1,37}
%e 10: {1,3} 155: {3,11} 334: {1,39}
%e 22: {1,5} 166: {1,23} 335: {3,19}
%e 25: {3,3} 187: {5,7} 341: {5,11}
%e 34: {1,7} 194: {1,25} 358: {1,41}
%e 46: {1,9} 205: {3,13} 365: {3,21}
%e 55: {3,5} 206: {1,27} 382: {1,43}
%e 62: {1,11} 218: {1,29} 391: {7,9}
%e 82: {1,13} 235: {3,15} 394: {1,45}
%e 85: {3,7} 253: {5,9} 415: {3,23}
%e 94: {1,15} 254: {1,31} 422: {1,47}
%e 115: {3,9} 274: {1,33} 451: {5,13}
%e 118: {1,17} 289: {7,7} 454: {1,49}
%e 121: {5,5} 295: {3,17} 466: {1,51}
%e 134: {1,19} 298: {1,35} 482: {1,53}
%p q:= n-> (l-> add(i[2], i=l)=2 and andmap(i->
%p numtheory[pi](i[1])::odd, l))(ifactors(n)[2]):
%p select(q, [$1..1000])[]; # _Alois P. Heinz_, Nov 23 2020
%t Select[Range[100],PrimeOmega[#]==2&&OddQ[Times@@PrimePi/@First/@FactorInteger[#]]&]
%Y A338911 is the even instead of odd version.
%Y A339003 is the squarefree case.
%Y A001221 counts distinct prime indices.
%Y A001222 counts prime indices.
%Y A001358 lists semiprimes, with odd/even terms A046315/A100484.
%Y A006881 lists squarefree semiprimes, with odd/even terms A046388/A100484.
%Y A289182/A115392 list the positions of odd/even terms of A001358.
%Y A300912 lists semiprimes with relatively prime indices.
%Y A318990 lists semiprimes with divisible indices.
%Y A338904 groups semiprimes by weight.
%Y A338906/A338907 are semiprimes of even/odd weight.
%Y A338898, A338912, and A338913 give the prime indices of semiprimes, with product A087794, sum A176504, and difference A176506.
%Y A338899, A270650, and A270652 give prime indices of squarefree semiprimes.
%Y A338909 lists semiprimes with non-relatively prime indices.
%Y Cf. A005117, A037143, A055684, A056239, A065516, A112798, A195017, A320655, A320732, A320892, A339004.
%K nonn
%O 1,1
%A _Gus Wiseman_, Nov 20 2020
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