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 A071525 Numbers n such that sigma(phi(n)) = reversal(n). 2
 1, 3, 304, 918, 23922, 2388063, 88423222968, 655516144546 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS There are no other terms up to 10^7. - Jason Earls, Jun 04 2002 There are no other terms up to 45*10^7. - Farideh Firoozbakht, Dec 26 2007 There are no other terms up to 10^10. - Donovan Johnson, Oct 24 2013 a(9) > 10^12. - Giovanni Resta, Nov 10 2017 LINKS EXAMPLE sigma(phi(304)) = 403 = reverse(304). MATHEMATICA Select[Range[10^5], DivisorSigma[1, EulerPhi[ # ]] == FromDigits[Reverse[IntegerDigits[ # ]]] &] CROSSREFS Cf. A000010, A000203, A135238. Sequence in context: A226500 A052505 A307020 * A157583 A218361 A085319 Adjacent sequences:  A071522 A071523 A071524 * A071526 A071527 A071528 KEYWORD base,nonn AUTHOR Joseph L. Pe, Jun 02 2002 EXTENSIONS More terms from Jason Earls, Jun 04 2002 Definition restored by Farideh Firoozbakht, Dec 26 2007 a(7)-a(8) from Giovanni Resta, Nov 10 2017 STATUS approved

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Last modified May 22 11:06 EDT 2022. Contains 353949 sequences. (Running on oeis4.)