A162527 Numbers k whose largest divisor <= sqrt(k) equals 7.

49, 56, 63, 70, 77, 84, 91, 98, 105, 119, 133, 147, 161, 175, 203, 217, 245, 259, 287, 301, 329, 343, 371, 413, 427, 469, 497, 511, 553, 581, 623, 679, 707, 721, 749, 763, 791, 889, 917, 959, 973, 1043, 1057, 1099, 1141, 1169, 1211, 1253, 1267, 1337, 1351

Offset

1,1

Comments

See A161344 for more information.

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Formula

Numbers k such that A033676(k)=7.

Maple

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

Mathematica

ld = 7;
selQ[n_] := AllTrue[Divisors[n], # <= ld || #^2 > n&];
Select[Range[ld, 200] ld, selQ] (* Jean-François Alcover, Apr 14 2020 *)
ld7Q[n_]:=Select[Divisors[n], #<=Sqrt[n]&][[-1]]==7; Select[Range[1400], ld7Q] (* Harvey P. Dale, Jan 13 2023 *)

Crossrefs

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

Sequence in context: A305358 A140388 A044863 * A028915 A345114 A090063

Adjacent sequences: A162524 A162525 A162526 * A162528 A162529 A162530

Keyword

easy,nonn

Author

Omar E. Pol, Jul 05 2009

Extensions

More terms from R. J. Mathar, Jul 13 2009

Status

approved