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 A309039 #48 Jun 11 2022 05:22:35 %S A309039 2,4,6,12,36,48,240 %N A309039 Highly composite numbers (A002182) that are not highly Brazilian (A329383). %C A309039 Is there a proof that this sequence is infinite? %C A309039 Indeed, from 1680 to 2882880, that is, during 26 successive terms (maybe more?), highly composite numbers are the same as highly Brazilian numbers. - _Bernard Schott_, Jul 12 2019 %e A309039 2 is a highly composite number (A002182) but is not in A329383 (where 1 is followed immediately by 7), so 2 is a term of this sequence. %e A309039 48 is highly composite with tau(48) = 10, and 48 = 66_7 = 44_11 = 33_15 = 22_33 so beta(48) = 4. We have also beta(40) = 4 with 40 = 1111_3 = 55_7 = 44_9 = 22_19 so 48 is not highly Brazilian. 48 is a term because it is highly composite but not highly Brazilian. - _Bernard Schott_, Jul 12 2019 %Y A309039 Cf. A002182 (highly composites), A329383 (highly Brazilian numbers), A279930 (highly composites and highly Brazilian numbers), A309493 (highly Brazilian numbers not highly composites). %K A309039 nonn,hard,more %O A309039 1,1 %A A309039 _J. Lowell_, Jul 08 2019