A333954 Numbers k such that A330575(k) = A330575(k+1).

14, 16101, 72926, 97101, 2872701, 7610324

Offset

1,1

Comments

a(7) > 6*10*8.

Links

Table of n, a(n) for n=1..6.

Thomas Fink, Recursively divisible numbers, arXiv:1912.07979 [math.NT], 2019.

Example

14 is a term since A330575(14) = A330575(15) = 26.

Mathematica

s[1] = 1; s[n_] := s[n] = n + DivisorSum[n, s[#] &, # < n &]; seq = {}; s1 = s[1]; Do[s2 = s[n]; If[s1 == s2, AppendTo[seq, n-1]]; s1 = s2, {n, 2, 10^5}]; seq

Crossrefs

Cf. A330575.

Similar sequences: A002961, A064115, A064125, A293183, A306985.

Sequence in context: A048913 A246623 A208194 * A104376 A053870 A283840

Adjacent sequences: A333951 A333952 A333953 * A333955 A333956 A333957

Keyword

nonn,more

Author

Amiram Eldar, Apr 11 2020

Status

approved