cp's OEIS Frontend

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.

A348101 Starts of runs of 5 consecutive numbers that have an equal number of unitary and nonunitary prime divisors (A348097).

This page as a plain text file.
%I A348101 #11 Sep 30 2021 17:03:02
%S A348101 906596,12133672,19293208,23542000,25793449,70289224,77449300,
%T A348101 130397524,316377124,359762848,371355172,395284372,415670200,
%U A348101 527032924,600284788,642788072,730243348,746696248,754642996,792007675,1153139048,1153702448,1338997372,1359156472
%N A348101 Starts of runs of 5 consecutive numbers that have an equal number of unitary and nonunitary prime divisors (A348097).
%C A348101 1744218747 is the least start of a run of 6 consecutive numbers. The next such run starts with 73840265847.
%H A348101 Amiram Eldar, <a href="/A348101/b348101.txt">Table of n, a(n) for n = 1..500</a>
%e A348101 906596 is a term since 906596 = 2^2 * 226649, 906596 + 1 = 906597 = 3^2 * 100733, 906596 + 2 = 906598 = 2 * 7^2 * 11 * 29^2, 906596 + 3 = 906599 = 71 * 113^2 and 906596 + 4 = 906600 = 2^3 * 3 * 5^2 * 1511 all have the same number of unitary and nonunitary prime divisors.
%t A348101 q[n_] := n == 1 || Count[(e = FactorInteger[n][[;; , 2]]), 1] == Length[e]/2; v = q /@ Range[5]; seq = {}; Do[v = Append[Drop[v, 1], q[k]]; If[And @@ v, AppendTo[seq, k - 4]], {k, 6, 3*10^7}]; seq
%Y A348101 Subsequence of A348097, A348098, A348099 and A348100.
%Y A348101 Cf. A335399.
%K A348101 nonn
%O A348101 1,1
%A A348101 _Amiram Eldar_, Sep 30 2021