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 A088949 #14 Mar 02 2025 07:59:56
%S A088949 4,8,9,16,25,27,32,49,64,81,105,121,125,128,169,231,243,256,289,315,
%T A088949 343,361,512,525,529,625,627,693,729,735,841,897,935,945,961,1024,
%U A088949 1155,1331,1369,1575,1581,1617,1681,1729,1849,1881,2048,2079,2187,2197,2205,2209
%N A088949 Composite numbers k such that (A006530(k) + A020639(k))/2 is an integer that divides k; special terms of A088948.
%H A088949 Amiram Eldar, <a href="/A088949/b088949.txt">Table of n, a(n) for n = 1..10000</a>
%e A088949 k = 315 = 3*3*5*7 (composite); (3 + 7)/2 = 5, which divides k.
%t A088949 q[k_] := CompositeQ[k] && Module[{p = FactorInteger[k][[;;, 1]], m}, m = (p[[1]] + p[[-1]]); EvenQ[m] && Divisible[k, m/2]]; Select[Range[2500], q] (* _Amiram Eldar_, Mar 01 2025 *)
%o A088949 (PARI) lista(nn) = {forcomposite(n=1, nn, my(f = factor(n)[,1], x = (vecmin(f) + vecmax(f))/2); if ((denominator(x)==1) && !(n % x), print1(n, ", ")););} \\ _Michel Marcus_, Jul 09 2018
%Y A088949 Cf. A006530, A020639, A088948, A088595, A046687.
%K A088949 nonn
%O A088949 1,1
%A A088949 _Labos Elemer_, Nov 20 2003
%E A088949 Edited by _Jon E. Schoenfield_, Jul 08 2018
%E A088949 More terms from _Michel Marcus_, Jul 09 2018