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Search: id:A062503
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| A062503 |
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Square-free numbers squared. |
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+0
3
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| 1, 4, 9, 25, 36, 49, 100, 121, 169, 196, 225, 289, 361, 441, 484, 529, 676, 841, 900, 961, 1089, 1156, 1225, 1369, 1444, 1521, 1681, 1764, 1849, 2116, 2209, 2601, 2809, 3025, 3249, 3364, 3481, 3721, 3844, 4225, 4356, 4489, 4761, 4900, 5041, 5329, 5476
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also, except for the initial term, numbers whose prime factors are squared. - Cino Hilliard (hillcino368(AT)gmail.com), Jan 25 2006
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
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n such that sumdiv(n, d, mu(d)*mu(n/d)) = 1 - Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 03 2004
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MATHEMATICA
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lst={}; Do[a=0; Do[If[FactorInteger[m][[n, 2]]!=2, a=1], {n, Length[FactorInteger[m]]}]; If[a==0, AppendTo[lst, m]], {m, 8!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Sep 27 2008]
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PROGRAM
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(PARI) je=[]; for(n=1, 200, if(issquarefree(n), je=concat(je, n^2), )); je
(PARI) { n=0; for (m=1, 10^5, if(issquarefree(m), write("b062503.txt", n++, " ", m^2); if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 08 2009]
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CROSSREFS
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Cf. A005117.
Sequence in context: A030140 A153158 A111245 this_sequence A063577 A087058 A046659
Adjacent sequences: A062500 A062501 A062502 this_sequence A062504 A062505 A062506
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Jul 09 2001
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