A230577 Positive integers that have exactly 6 odd divisors.

45, 63, 75, 90, 99, 117, 126, 147, 150, 153, 171, 175, 180, 198, 207, 234, 243, 245, 252, 261, 275, 279, 294, 300, 306, 325, 333, 342, 350, 360, 363, 369, 387, 396, 414, 423, 425, 468, 475, 477, 486, 490

Offset

1,1

Comments

Numbers that can be formed in exactly 5 ways by summing sequences of 2 or more consecutive integers.

Column 6 of A266531. - Omar E. Pol, Apr 03 2016

Numbers n such that the symmetric representation of sigma(n) has 6 subparts. - Omar E. Pol, Dec 28 2016

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[500], Count[Divisors[#], _?OddQ]==6&] (* Harvey P. Dale, Mar 25 2015 *)

Prog

(PARI) is(n)=numdiv(n>>valuation(n, 2))==6 \\ Charles R Greathouse IV, Oct 28 2013

Crossrefs

Cf. A000203, A001227, A077646, A237593, A279387, A266531.

Numbers with k odd divisors (k = 1..10): A000079, A038550, A072502, apparently A131651, A267696, this sequence, A267697, A267891, A267892, A267893.

Sequence in context: A242264 A333326 A077646 * A336555 A175761 A360769

Adjacent sequences: A230574 A230575 A230576 * A230578 A230579 A230580

Keyword

nonn

Author

Philippe Beaudoin, Oct 23 2013

Status

approved