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 A307117 #9 Mar 26 2019 20:14:32 %S A307117 8,27,105,125,231,343,627,897,935,1331,1581,1729,2197,2465,2967,3525, %T A307117 4123,4301,4715,4913,5487,6859,7035,7685,7881,9717,10707,11339,12167, %U A307117 14993,16377,17353,17655,20213,20915,23779,24389,24765,25327,26331,26765,29341,29607 %N A307117 Numbers x that are equal to lpf(x)*gpf(x)*(lpf(x)+gpf(x))/2, where lpf(x) and gpf(x) are the least and the greatest prime factors of x: A020639 and A006530. %C A307117 This is A307108 with terms such that lpf(x)=gpf(x), that is, with cubes of primes. %Y A307117 Cf. A000040, A020639, A006530, A307108. %Y A307117 Cf. A262723 is the subsequence with terms such that lpf(x)!=gpf(x), and (lpf(x)+gpf(x))/2 a prime. %K A307117 nonn %O A307117 1,1 %A A307117 _Alex Ratushnyak_, Mar 25 2019