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.

A351382 Products of four distinct primes between sphenic numbers (products of 3 distinct primes).

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%I A351382 #38 Aug 12 2023 14:55:56
%S A351382 7566,9086,10506,15170,17170,18734,18886,18906,19670,20306,20586,
%T A351382 21594,21606,22630,23218,23694,23902,25070,25466,25670,26466,26554,
%U A351382 26610,27714,28302,28614,29562,30514,30710,32054,32154,32334,34238,34706,35014,37114,38590,39354
%N A351382 Products of four distinct primes between sphenic numbers (products of 3 distinct primes).
%C A351382 Numbers with at least one prime exponent greater than 1 are excluded here.
%e A351382    7566 = 2*3*13*97  (between  7565 = 5 * 17 * 89  and  7567 = 7*23*47).
%e A351382    9086 = 2*7*11*59  (between  9085 = 5 * 23 * 79  and  9087 = 3*13*233).
%e A351382   10506 = 2*3*17*103 (between 10505 = 5 * 11 * 191 and 10507 = 7*19*79).
%e A351382   15170 = 2*5*37*41  (between 15169 = 7 * 11 * 197 and 15171 = 3*13*389).
%t A351382 q[n_, m_] := Module[{f = FactorInteger[n]}, Length[f] == m && Max[f[[;; , 2]]] == 1]; Select[Range[40000], q[#, 4] && q[# - 1, 3] && q[# + 1, 3] &] (* _Amiram Eldar_, Mar 28 2022 *)
%Y A351382 Cf. A007304.
%K A351382 nonn
%O A351382 1,1
%A A351382 _Massimo Kofler_, Mar 28 2022