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 A277336 #8 Nov 05 2016 08:05:50
%S A277336 6,12,24,35,61,76,96,118,146,162,230,245,338,362,384,426,444,460,472,
%T A277336 580,584,605,642,645,664,697,718,740,790,804,812,814,830,852,877,920,
%U A277336 926,954,979,1098,1178,1192,1216,1332,1334,1406,1415,1446,1452,1454,1459
%N A277336 Numbers n for which the sum of the odd members and the sum of the even members in the Collatz (3x+1) trajectory are both semiprime.
%C A277336 The corresponding pairs of semiprimes are (9, 46), (9, 58), (9, 82), (94, 446), (178, 838), (95, 538), (9, 226), (411, 1894), (20499, 82366), (259, 1366), (493, 2446), (362, 1942), ...
%H A277336 Charles R Greathouse IV, <a href="/A277336/b277336.txt">Table of n, a(n) for n = 1..10000</a>
%e A277336 6 is in the sequence because the Collatz trajectory is 6 -> 3 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1 => the sum of the odd members is 3 + 5 + 1 = 9 = 3*3 and the sum of the even members is 6 + 10 + 16 + 8 + 4 + 2 = 46 = 2*23.
%t A277336 coll[n_]:=NestWhileList[If[EvenQ[#],#/2,3#+1]&,n,#>1&];a:=Select[coll[n],OddQ[#]&];b:=Select[coll[n],EvenQ[#]&];Do[s1=Sum[a[[i]],{i,1,Length[a]}];s2=Sum[b[[j]],{j,1,Length[b]}];If[PrimeOmega[s1]==2&&PrimeOmega[s2]==2,Print[n]],{n,1,1500}]
%o A277336 (PARI) is(n)=my(e,o=1); while(n>1, if(n%2, o+=n; n+=2*n+1, e+=n; n/=2)); isprime(e/2) && bigomega(o)==2 \\ _Charles R Greathouse IV_, Oct 09 2016
%Y A277336 Cf. A001358, A213909, A213916, A275866.
%K A277336 nonn
%O A277336 1,1
%A A277336 _Michel Lagneau_, Oct 09 2016