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A353346 Numbers k such that the elements of the continued fraction of the abundancy index of k and k+1 are anagrams of each other. 3
2084564, 11784194, 13667268, 52820326, 68397891, 101183694, 128247668, 135641787, 137681487, 170542955, 266319572, 284966486, 384109196, 386860419, 482419526, 483785771, 546800667, 579468939, 606809224, 622241109, 703636544, 737703005, 829965829, 830993564, 834224684, 973986250 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..108

EXAMPLE

2084564 is a term since the sequences of elements of the continued fractions of sigma(2084564)/2084564 = 941472/521141 and sigma(2084565)/2084565 = 1270656/694855, {1, 1, 4, 5, 1, 8, 1, 5, 2, 4, 1, 7, 3} and {1, 1, 4, 1, 5, 8, 1, 2, 4, 7, 3, 1, 5} respectively, are anagrams of each other.

MATHEMATICA

ab[n_] := Sort[ContinuedFraction[DivisorSigma[-1, n]]]; seq[max_] := Module[{s = {}, n = 2, c = 0, ab1 = ab[1], ab2}, While[n < max, ab2 = ab[n]; If[ab1 == ab2, AppendTo[s, n - 1]]; ab1 = ab2; n++]; s]; seq[1.4*10^7]

CROSSREFS

Cf. A000203 (sigma), A069567, A017665, A017666, A349685, A353345, A353347.

Sequence in context: A155126 A234469 A212728 * A234420 A115505 A126435

Adjacent sequences:  A353343 A353344 A353345 * A353347 A353348 A353349

KEYWORD

nonn

AUTHOR

Amiram Eldar, Apr 15 2022

STATUS

approved

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Last modified June 29 17:37 EDT 2022. Contains 354913 sequences. (Running on oeis4.)