A162529 Numbers k whose largest divisor <= sqrt(k) equals 9.

81, 90, 99, 108, 117, 126, 135, 153, 162, 171, 189, 207, 243, 261, 279, 333, 369, 387, 423, 477, 531, 549, 603, 639, 657, 711, 747, 801, 873, 909, 927, 963, 981, 1017, 1143, 1179, 1233, 1251, 1341, 1359, 1413, 1467, 1503, 1557, 1611, 1629, 1719, 1737, 1773

Offset: 1

Author

Omar E. Pol, Jul 05 2009

Keywords

• easy
• nonn

Comments

See A161344 for more information.

Crossrefs

Cf. A033676, A008578, A161344, A161345, A161424, A161835, A162526, A162527, A162528, A162530, A162531, A162532.

Programs

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 2500 do if A033676(n) = 9 then printf("%d,",n) ; fi; od: # R. J. Mathar, Jul 13 2009

Mathematica

lst = {}; For[n = 1, n <= 5000, n++, If[Last[Select[Divisors[n], # <= Sqrt@n &]] == 9, PrependTo[lst, n]]]; Reverse@lst (* Jasper Mulder (jasper.mulder(AT)planet.nl), Jul 14 2009 *)

Formula

Numbers k such that A033676(k)=9.

Extensions

More terms from R. J. Mathar and Jasper Mulder (jasper.mulder(AT)planet.nl), Jul 13 2009