A068351 Numbers n such that n*tau(n)>prime(3*n) where tau(n)=A000005(n).

720, 840, 900, 960, 1008, 1080, 1200, 1260, 1320, 1440, 1512, 1560, 1584, 1620, 1680, 1800, 1848, 1872, 1890, 1920, 1980, 2016, 2040, 2100, 2160, 2184, 2280, 2310, 2340, 2376, 2400, 2520, 2640, 2688, 2700, 2730, 2760, 2772, 2808, 2856, 2880, 2940

Offset

1,1

Comments

Only 13 of the first 2500 terms are odd, and each one of them is a multiple of 5. - Harvey P. Dale, Jun 15 2014

Links

Harvey P. Dale, Table of n, a(n) for n = 1..2500

Mathematica

Select[Range[3000], # DivisorSigma[0, #]>Prime[3#]&] (* Harvey P. Dale, Jun 15 2014 *)

Prog

(PARI) for(n=1, 3300, if(n*numdiv(n)>prime(3*n), print1(n, ", ")))

Crossrefs

Sequence in context: A145226 A056467 A056457 * A067892 A337036 A257416

Adjacent sequences: A068348 A068349 A068350 * A068352 A068353 A068354

Keyword

easy,nonn

Author

Benoit Cloitre, Feb 28 2002

Status

approved