cp's OEIS Frontend

A285386 Lexicographically earliest sequence of distinct positive terms such that the product of two consecutive terms is divisible by p^4 for some prime p.

%I A285386 #11 Apr 20 2017 12:34:06
%S A285386 1,16,2,8,4,12,20,24,6,27,3,32,5,48,7,64,9,18,36,28,40,10,56,14,72,22,
%T A285386 80,11,81,13,96,15,54,21,108,30,88,26,104,34,112,17,128,19,144,23,160,
%U A285386 25,50,75,100,44,52,60,68,76,84,92,116,120,38,136,42,135,33
%N A285386 Lexicographically earliest sequence of distinct positive terms such that the product of two consecutive terms is divisible by p^4 for some prime p.
%C A285386 This sequence is a permutation of the natural numbers.
%H A285386 Rémy Sigrist, <a href="/A285386/b285386.txt">Table of n, a(n) for n = 1..10000</a>
%H A285386 Rémy Sigrist, <a href="/A285386/a285386.txt">C++ program for A285386</a>
%H A285386 Rémy Sigrist, <a href="/A285386/a285386.png">Scatterplot of the first 100000 terms</a>
%H A285386 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%e A285386 The first terms, alongside the primes p such that p^4 divides a(n)*a(n+1), are:
%e A285386 n       a(n)    p
%e A285386 --      ----    -
%e A285386 1       1       2
%e A285386 2       16      2
%e A285386 3       2       2
%e A285386 4       8       2
%e A285386 5       4       2
%e A285386 6       12      2
%e A285386 7       20      2
%e A285386 8       24      2
%e A285386 9       6       3
%e A285386 10      27      3
%e A285386 11      3       2
%e A285386 12      32      2
%e A285386 13      5       2
%e A285386 14      48      2
%e A285386 15      7       2
%e A285386 16      64      2
%e A285386 17      9       3
%e A285386 18      18      3
%e A285386 19      36      2
%e A285386 20      28      2
%e A285386 ...
%e A285386 165     95      2
%e A285386 166     432     2, 3
%e A285386 167     87      3
%e A285386 ...
%Y A285386 Cf. A285296.
%K A285386 nonn
%O A285386 1,2
%A A285386 _Rémy Sigrist_, Apr 18 2017