A348415 - OEIS

A348415

Numbers k such that k and k+1 have the same denominator of the harmonic means of their divisors.

12, 88, 180, 266, 321, 604, 4277, 4364, 8632, 15861, 18720, 28461, 47613, 63546, 97412, 98907, 135078, 137333, 154132, 179621, 185776, 192699, 203709, 265489, 284883, 344217, 383466, 517610, 604197, 876469, 1089604, 1277518, 1713865, 1839123, 1893268, 2349390

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OFFSET

1,1

COMMENTS

Numbers k such that A099378(k) = A099378(k+1).

The common denominators of k and k+1 are 7, 45, 91, 30, 36, 133, 96, 637, ...

Can 3 consecutive numbers have the same denominator of harmonic mean of divisors? There are no such numbers below 10^10.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..300

EXAMPLE

12 is a term since the harmonic means of the divisors of 12 and 13 are 18/7 and 13/7, respectively, and both have the denominator 7.

MATHEMATICA