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 A384960 #12 Jul 11 2025 16:19:49
%S A384960 1001,105,231,30,42,70,110,66,78,170,102,114,138,370,174,826,222,246,
%T A384960 258,318,354,402,438,498,534,582,654,762,786,894,978,1038,1158,1338,
%U A384960 1506,1542,1758,1986,2082,2202,2334,2598,2922,3126,3462,3918,4098,4398,4614,5262
%N A384960 a(n) = smallest sphenic number k such that A010846(k) = n.
%C A384960 a(1) = A384000(3) = 1001; A010846(1001) = A024718(3) = 15; 1001 is the smallest number k with 3 distinct prime factors that has the smallest possible number of terms in row k of A162306, i.e., m <= k such that rad(m) | k.
%C A384960 For n > 30, 6 | a(n).
%H A384960 Michael De Vlieger, <a href="/A384960/b384960.txt">Table of n, a(n) for n = 15..300</a>
%H A384960 Michael De Vlieger, <a href="/A384960/a384960.png">Plot of terms k = p^a*q^b*r^c, primes p < q < r, in row a(n) of A162306</a>, n = 15..50, at (x,y,z) = (a,b,c). For a(n) there are n blocks in each diagram.
%H A384960 Michael De Vlieger, <a href="/A384960/a384960.txt">Mathematica code</a>.
%e A384960 Table of a(n) indicating prime factors and S, where S = {ceiling(log_p a(n))} for all primes p that divide a(n), in order of the magnitude of p.
%e A384960 Prime power factor
%e A384960 1111223344455
%e A384960 n m=a(n) pi(facs(m)) S 23571379391713739
%e A384960 -------------------------------------------------
%e A384960 15 1001 4.5.6 4.3.3 ...111
%e A384960 16 105 2.3.4 5.3.3 .111
%e A384960 17 231 2.4.5 5.3.3 .1.11
%e A384960 18 30 1.2.3 5.4.3 111
%e A384960 19 42 1.2.4 6.4.2 11.1
%e A384960 20 70 1.3.4 7.3.3 1.11
%e A384960 21 110 1.3.5 7.3.2 1.1.1
%e A384960 22 66 1.2.5 7.4.2 11..1
%e A384960 23 78 1.2.6 7.4.2 11...1
%e A384960 24 170 1.3.7 8.4.2 1.1...1
%e A384960 25 102 1.2.7 7.5.2 11....1
%e A384960 26 114 1.2.8 7.5.2 11.....1
%e A384960 27 138 1.2.9 8.5.2 11......1
%e A384960 28 370 1.3.12 9.4.2 1.1........1
%e A384960 29 174 1.2.10 8.5.2 11.......1
%e A384960 30 826 1.4.17 10.4.2 1..1............1
%e A384960 31 222 1.2.12 8.5.2 11.........1
%e A384960 32 246 1.2.13 8.6.2 11..........1
%e A384960 33 258 1.2.14 9.6.2 11...........1
%e A384960 34 318 1.2.16 9.6.2 11.............1
%t A384960 (* See Mathematica code link for function definitions for kappaomega and theta *)
%t A384960 s = kappaomega[3, 6000]; t = Map[theta, s];
%t A384960 Map[s[[FirstPosition[t, #][[1]] ]] &, Union[t]]
%Y A384960 Cf. A007304, A007947, A010846, A024718, A162306, A384000.
%K A384960 nonn
%O A384960 15,1
%A A384960 _Michael De Vlieger_, Jul 06 2025