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 A373645 #12 May 20 2025 14:52:41 %S A373645 2,11,114,894,13155,127041,2219826,44489860,1023485967,26436195405, %T A373645 755182183459,23609378957430,802775563829902,29480898988179429, %U A373645 1162849454580682365 %N A373645 The smallest number whose prime factor concatenation, as well as the number itself, when written in base n, contains all digits 0,1,...,(n-1). %C A373645 For base 2 and base 3 the number is prime; are there other bases where this is also true? %e A373645 a(5) = 894 = 12034_5 which contains all the digits 0..4, and 894 = 2 * 3 * 149 = 2_5 * 3_5 * 1044_5, and the factors contain all digits 0..4. %e A373645 a(10) = 1023485967 which contains all digits 0..9, and 1023485967 = 3 * 3 * 7 * 16245809, and the factors contain all digits 0..9. %e A373645 a(15) = 29480898988179429 = 102345C86EA7BD9_15 which contains all the digits 0..E, and 29480898988179429 = 3 * 7 * 17 * 139 * 594097474723 = 3_15 * 7_15 * 12_15 * 94_15 * 106C1A8B5ED_15, and the factors contain all digits 0..E. %Y A373645 Cf. A372309, A358003, A372384, A372280, A372295, A372249, A027746. %Y A373645 Cf. A374225. %K A373645 nonn,base,more %O A373645 2,1 %A A373645 _Scott R. Shannon_, Jun 12 2024