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 A117360 #10 Apr 30 2016 19:18:24 %S A117360 2,3,4,5,10,11,23,25,29,34,38,40,41,46,52,53,55,57,76,77,83,89,91,93, %T A117360 106,113,118,123,129,130,131,133,143,145,159,161,169,171,172,173,177, %U A117360 179,185,191,201,203,205,206,212,213,218,220,226,233,235,238,239,251 %N A117360 Numbers m such that m and 2*m+1 have the same number of prime factors. %C A117360 A001222(a(n)) = A001222(2*a(n)+1); %C A117360 Sophie Germain primes are a subsequence, see A005384. %H A117360 R. Zumkeller, <a href="/A117360/b117360.txt">Table of n, a(n) for n = 1..10000</a> %e A117360 m=52=2*2*13, 2*52+1=105=3*5*7, therefore 52 is a term. %t A117360 Select[Range[255], PrimeOmega[#] == PrimeOmega[2 # + 1] &] (* _Ivan Neretin_, Apr 30 2016 *) %o A117360 (PARI) is(n)=bigomega(n)==bigomega(2*n+1) \\ _Charles R Greathouse IV_, Apr 30 2016 %Y A117360 Cf. A068406. %K A117360 nonn %O A117360 1,1 %A A117360 _Reinhard Zumkeller_, Mar 10 2006