A162527 - OEIS

%I #14 Jan 13 2023 13:35:46

%S 49,56,63,70,77,84,91,98,105,119,133,147,161,175,203,217,245,259,287,

%T 301,329,343,371,413,427,469,497,511,553,581,623,679,707,721,749,763,

%U 791,889,917,959,973,1043,1057,1099,1141,1169,1211,1253,1267,1337,1351

%N Numbers k whose largest divisor <= sqrt(k) equals 7.

%C See A161344 for more information.

%H Nathaniel Johnston, <a href="/A162527/b162527.txt">Table of n, a(n) for n = 1..10000</a>

%F Numbers k such that A033676(k)=7.

%p A033676 := proc(n) local dvs; dvs := sort(convert(numtheory[divisors](n),list)) ; op(floor((nops(dvs)+1)/2) ,dvs) ; end: for n from 1 to 2000 do if A033676(n) = 7 then printf("%d,",n) ; fi; od: # _R. J. Mathar_, Jul 13 2009

%t ld = 7;

%t selQ[n_] := AllTrue[Divisors[n], # <= ld || #^2 > n&];

%t Select[Range[ld, 200] ld, selQ] (* _Jean-François Alcover_, Apr 14 2020 *)

%t ld7Q[n_]:=Select[Divisors[n],#<=Sqrt[n]&][[-1]]==7; Select[Range[1400],ld7Q] (* _Harvey P. Dale_, Jan 13 2023 *)

%Y Cf. A033676, A008578, A161344, A161345, A161424, A161835, A162526, A162528, A162529, A162530, A162531, A162532.

%K easy,nonn

%O 1,1

%A _Omar E. Pol_, Jul 05 2009

%E More terms from _R. J. Mathar_, Jul 13 2009