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A168086 Numbers n such that d(n)=nonisolated number. 1
1, 4, 9, 16, 24, 25, 30, 36, 40, 42, 48, 49, 54, 56, 64, 66, 70, 78, 80, 81, 88, 100, 102, 104, 105, 110, 112, 114, 120, 121, 128, 130, 135, 136, 138, 144, 152, 154, 162, 165, 168, 169, 170, 174, 176, 182, 184, 186, 189, 190, 192, 195, 196, 208, 210, 216, 222 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A000005 = A167759 U A168086. Where 0,1,3,5,7,8,9,10,11,13,14,15,16,17,19,20,21,22,.. are nonisolated numbers A167707. The nonisolated numbers of divisors of n. The positions of isolated numbers in A000005.

LINKS

Table of n, a(n) for n=1..57.

FORMULA

A000005(a(n))=nonisolated number.

EXAMPLE

A000005(a(1)=1)=1, A000005(a(2)=4)=3, A000005(a(3)=9)=3.

CROSSREFS

Cf. A000005, A167759, A167707.

Sequence in context: A009850 A009853 A008030 * A176238 A139588 A320894

Adjacent sequences:  A168083 A168084 A168085 * A168087 A168088 A168089

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Nov 18 2009

EXTENSIONS

Corrected (132, 140, 148 removed, 152 inserted etc.) by R. J. Mathar, Jun 04 2010

STATUS

approved

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Last modified October 6 23:36 EDT 2022. Contains 357270 sequences. (Running on oeis4.)