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 A082955 Numbers k such that sigma(k*phi(k)) = sigma(k)^2. 1
 1, 87, 1257, 42921, 65307, 68037, 89067, 112803, 116619, 186231, 252417, 350283, 356259, 380559, 435993, 477723, 492771, 527781, 635259, 672051, 708111, 866379, 991479, 1062723, 1078509, 1347699, 1352199, 1353873, 1449363, 1561431, 1838019 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Amiram Eldar, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Range[2000000], DivisorSigma[1, # EulerPhi[#]]== DivisorSigma[1, #]^2&] (* Harvey P. Dale, Mar 27 2011 *) PROG (PARI) for(n=1, 2000000, if(sigma(n*eulerphi(n))==sigma(n)^2, print1(n, ", "))) CROSSREFS Cf. A000010, A000203. Sequence in context: A093287 A231218 A186054 * A201154 A171344 A200533 Adjacent sequences: A082952 A082953 A082954 * A082956 A082957 A082958 KEYWORD nonn AUTHOR Benoit Cloitre, May 26 2003 EXTENSIONS More terms from Rick L. Shepherd, Jun 05 2003 STATUS approved

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Last modified June 18 08:27 EDT 2024. Contains 373472 sequences. (Running on oeis4.)