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A070226
Numbers n such that the squarefree kernel of n is equal to the number of divisors of n.
2
1, 2, 9, 12, 18, 80, 448, 625, 720, 1200, 1250, 1620, 2025, 4032, 4050, 5625, 7500, 9408, 11250, 11264, 20412, 35721, 53248, 71442, 101376, 117649, 235298, 280000, 371712, 479232, 768320, 907200, 1058841, 1114112, 1270080, 1411788, 1750000
OFFSET
1,2
COMMENTS
Numbers n such that A007947(n)/A000005(n) = 1. [From Ctibor O. Zizka, Feb 05 2009]
Conjecture : If A000005(n) divides A007947(n) for some n, then A007947(n)=A000005(n). [From Ctibor O. Zizka, Feb 05 2009]
LINKS
MATHEMATICA
Select[Range[2000000], DivisorSigma[0, #]==Times@@Transpose[ FactorInteger[#]][[1]]&] (* Harvey P. Dale, Apr 09 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, May 07 2002
STATUS
approved