login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A365885 Starts of run of 3 consecutive integers that are terms of A365883. 4

%I #8 Sep 23 2023 15:01:35

%S 228123,903123,1121875,2253123,2928123,3146875,3821875,4278123,

%T 5846875,6303123,6978123,7196875,7871875,9003123,9221875,9896875,

%U 10353123,11028123,11246875,12378123,13053123,13271875,13946875,14403123,15971875,16428123,17103123,17321875

%N Starts of run of 3 consecutive integers that are terms of A365883.

%C Numbers of the form 4*k+2 are not terms of A365883. Therefore there are no runs of 4 or more consecutive integers.

%C Since the middle integer in each triple is not divisible by 8, all the terms of this sequence are of the form 8*k+3.

%C The numbers of terms not exceeding 10^k, for k = 6, 7, ..., are 2, 16, 158, 1585, 15853, 158540, ... . Apparently, the asymptotic density of this sequence exists and equals 1.585...*10^(-6).

%H Amiram Eldar, <a href="/A365885/b365885.txt">Table of n, a(n) for n = 1..10000</a>

%e 228123 = 3^3 * 7 * 17 * 71 is a term since its least prime factor, 3, is equal to its exponent, the least prime factor of 228123 = 2^2 * 13 * 41 * 107, 2, is equal to its exponent, and the least prime factor of 228125 = 5^5 * 73, 5, is also equal to its exponent.

%t q[n_] := Equal @@ FactorInteger[n][[1]]; Select[8*Range[125000] + 3, AllTrue[# + {0, 1, 2}, q] &]

%o (PARI) is(n) = #Set(factor(n)[1,]) == 1;

%o lista(kmax) = forstep(k = 3, kmax, 8, if(is(k) && is(k+1) && is(k+2), print1(k, ", ")));

%Y Subsequence of A017101, A365883, A365884 and A365891.

%K nonn,easy

%O 1,1

%A _Amiram Eldar_, Sep 22 2023

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 7 03:39 EDT 2024. Contains 375008 sequences. (Running on oeis4.)