

A267697


Numbers with 7 odd divisors.


8



729, 1458, 2916, 5832, 11664, 15625, 23328, 31250, 46656, 62500, 93312, 117649, 125000, 186624, 235298, 250000, 373248, 470596, 500000, 746496, 941192, 1000000, 1492992, 1771561, 1882384, 2000000, 2985984, 3543122, 3764768, 4000000, 4826809, 5971968, 7086244, 7529536, 8000000, 9653618
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Positive integers that have exactly seven odd divisors.
Numbers n such that the symmetric representation of sigma(n) has 7 subparts.  Omar E. Pol, Dec 28 2016
Numbers that can be formed in exactly 6 ways by summing sequences of 2 or more consecutive positive integers.  Julie Jones, Aug 13 2018
Numbers of the form p^6 * 2^k where p is an odd prime.  David A. Corneth, Aug 14 2018


LINKS



FORMULA



PROG

(PARI) isok(n) = sumdiv(n, d, (d%2)) == 7; \\ Michel Marcus, Apr 03 2016
(PARI) upto(n) = {my(res = List()); forprime(p = 3, sqrtnint(n, 6), listput(res, p^6)); q = #res; for(i = 1, q, odd = res[i]; for(j = 1, logint(n \ odd, 2), listput(res, odd <<= 1))); listsort(res); res} \\ David A. Corneth, Aug 14 2018


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



EXTENSIONS



STATUS

approved



