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 A353347 Numbers k such that the elements of the continued fraction of phi(k)/k and phi(k+1)/(k+1) are anagrams of each other. 2
 1287, 96074, 5600160, 18486908, 41746312, 78700687, 211818591, 346666215, 535185325, 600248114, 617086359, 682116194, 972901517, 1326113558, 1397946770, 1404159416, 1785588903, 2090593128, 2286664100, 2349999964, 2396173329, 3154287487, 4029358361, 5401346573 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..24. EXAMPLE 1287 is a term since the sequences of elements of the continued fractions of phi(1287)/1287 = 80/143 and phi(1288)/1288 = 66/161, {0, 1, 1, 3, 1, 2, 2, 2} and {0, 2, 2, 3, 1, 1, 1, 2} respectively, are anagrams of each other. MATHEMATICA r[n_] := Sort[ContinuedFraction[EulerPhi[n]/n]]; seq[max_] := Module[{s = {}, n = 2, c = 0, r1 = r[1], r2}, While[n < max, r2 = r[n]; If[r1 == r2, AppendTo[s, n - 1]]; r1 = r2; n++]; s]; seq[6*10^6] CROSSREFS Cf. A000010 (phi), A069567, A076512, A109395, A342866, A353345, A353346. Sequence in context: A252116 A084803 A104399 * A232253 A140914 A239436 Adjacent sequences: A353344 A353345 A353346 * A353348 A353349 A353350 KEYWORD nonn AUTHOR Amiram Eldar, Apr 15 2022 STATUS approved

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Last modified March 2 14:13 EST 2024. Contains 370489 sequences. (Running on oeis4.)