This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A086096 #12 Feb 17 2025 15:12:52 %S A086096 15,39,46,51,57,58,77,85,86,95,106,111,119,123,141,142,159,166,169, %T A086096 177,178,183,187,201,202,209,215,219,221,226,235,237,249,267,278,287, %U A086096 291,298,303,305,323,326,329,335,365,371,377,393,394,407,411,413,417,427 %N A086096 Semiprimes with a semiprime number of 1's in their binary representation. %H A086096 Amiram Eldar, <a href="/A086096/b086096.txt">Table of n, a(n) for n = 1..10000</a> %e A086096 The sixth semiprime = 15 = '1111' with four 1's, so 15 is a term. %t A086096 binWt[n_] := DigitCount[n, 2, 1]; seqQ[n_] := PrimeOmega[n] == 2 && PrimeOmega[binWt[n]] == 2; Select[Range[500], seqQ] (* _Amiram Eldar_, Dec 14 2019 *) %t A086096 Select[Range[500],PrimeOmega[#]==PrimeOmega[DigitCount[#,2,1]]==2&] (* _Harvey P. Dale_, Feb 17 2025 *) %Y A086096 Cf. A001358, A000120, A086097. %K A086096 nonn,base %O A086096 1,1 %A A086096 _Jason Earls_, Jul 09 2003