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A267893 Numbers with 10 odd divisors. 8
405, 567, 810, 891, 1053, 1134, 1377, 1539, 1620, 1782, 1863, 1875, 2106, 2268, 2349, 2511, 2754, 2997, 3078, 3240, 3321, 3483, 3564, 3726, 3750, 3807, 4212, 4293, 4375, 4536, 4698, 4779, 4941, 5022, 5427, 5508, 5751, 5913, 5994, 6156, 6399, 6480, 6642, 6723, 6875, 6966, 7128, 7203, 7209, 7452, 7500, 7614, 7857, 8125 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Positive integers that have exactly 10 odd divisors.

Numbers n such that the symmetric representation of sigma(n) has 10 subparts. - Omar E. Pol, Dec 29 2016

Numbers that can be formed in exactly 9 ways by summing sequences of 2 or more consecutive positive integers. - Julie Jones, Aug 13 2018

LINKS

Muniru A Asiru, Table of n, a(n) for n = 1..5000

FORMULA

A001227(a(n)) = 10.

MATHEMATICA

Select[Range@ 8125, Length@ Select[Divisors@ #, OddQ] == 10 &] (* Michael De Vlieger, Dec 30 2016 *)

PROG

(PARI) isok(n) = sumdiv(n, d, (d%2)) == 10; \\ after Michel Marcus

(GAP) A:=List([1..10000], n->DivisorsInt(n));; B:=List([1..Length(A)], i->Filtered(A[i], IsOddInt));;

a:=Filtered([1..Length(B)], i->Length(B[i])=10); # Muniru A Asiru, Aug 14 2018

CROSSREFS

Column 10 of A266531.

Cf. A001227, A038547, A237593, A279387.

Numbers with exactly k odd divisors (k = 1..10): A000079, A038550, A072502, apparently A131651, A267696, A230577, A267697, A267891, A267892, this sequence.

Sequence in context: A185638 A198536 A169904 * A151745 A204636 A224527

Adjacent sequences:  A267890 A267891 A267892 * A267894 A267895 A267896

KEYWORD

nonn

AUTHOR

Omar E. Pol, Apr 03 2016

STATUS

approved

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Last modified December 10 17:12 EST 2018. Contains 318049 sequences. (Running on oeis4.)