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 A066732 Least k such that the least factor of k^Phi(k) -1 is the n-th prime. 0
 3, 4, 6, 18, 150, 60, 30, 22440, 120360, 44880, 5610, 11730, 8160, 473280, 277440, 131070, 548760, 920040, 750720, 440130, 329970, 27030, 5689560, 522240, 1020, 3028890, 2639760, 6866130, 251430, 134130, 7481190, 2390880, 2664240, 9926130 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 18^Phi(18)-1 = 18^6-1 = 34012223 = 7^3 * 17 * 19 * 307. Therefore since 7, the fourth prime, is the least prime in the factorization, a(4) = 18. MATHEMATICA a = Table[0, {53} ]; Do[b = 1; While[ PowerMod[n, EulerPhi[n], Prime[b]] != 1, b++ ]; If[ a[[b]] == 0, a[[b]] = n], {n, 3, 10^6} ] CROSSREFS Cf. A066699. Sequence in context: A138577 A298149 A136242 * A304679 A265735 A038520 Adjacent sequences:  A066729 A066730 A066731 * A066733 A066734 A066735 KEYWORD nonn AUTHOR Robert G. Wilson v, Jan 15 2002 STATUS approved

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Last modified November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)