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 A380530 #30 May 09 2025 16:19:28 %S A380530 1,4,10,42,366,3246,37266,631266,11563926,271591926 %N A380530 Positions of records in A380528. %C A380530 Questions: Are all terms squarefree after 4, and do all terms end (in base ten) with digit 6 from the fifth term onward? Is the sequence infinite? Are there any terms with more than four prime factors? See also the conjecture given in A380475, and A380476. %C A380530 For n = 1..10, A380528(a(n)) = A008578(n). If a(11) exists, it is > 2^30. %C A380530 Note that for squarefree n with exactly 5 prime factors (A046387), it might be possible that primes obtained as A380528(A046387(.)) has no upper limit. First k in A046387 such that A380528(k) is a prime 2 .. 17 are: 15015, 2730, 2310, 83886, 1551066, 71559186, 1245223986. See also the last two examples in A380470 for two similar cases with exactly 6 prime factors. - _Antti Karttunen_, May 08 2025 %H A380530 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>. %Y A380530 Cf. A008578 (conjectured to give the record values), A046387, A380528, A380459, A380468, A380470, A380475, A380476. %K A380530 nonn,hard,more %O A380530 1,2 %A A380530 _Antti Karttunen_, Feb 09 2025