A331017 Numbers that equal to the sum of their iterated absolute alternating sum-of-divisors function (A206369).

3, 10, 21, 63, 104, 152, 170, 358, 567, 651, 3826, 4664, 5583, 5943, 39248, 943228, 1906503, 9166540, 35702868, 701792828, 825415941, 2275142000, 5805372939

Offset: 1

Author

Amiram Eldar, Jan 06 2020

Keywords

• nonn
• more

Examples

			10 is a term since the iterations of A206369 with a starting value of 10 give A206369(10) = 4, A206369(4) = 3, A206369(3) = 2, and A206369(2) = 1, whose sum is 4 + 3 + 2 + 1 = 10.
		

Crossrefs

Cf. A082897, A206369, A330786 (number of iterations).

Programs

Mathematica

f[p_, e_] := Sum[(-1)^(e - k)*p^k, {k, 0, e}]; s[1] = 1; s[n_] := s[n] = Times @@ (f @@@ FactorInteger[n]); Select[Range[1000], Plus @@ FixedPointList[s, #] == 2 # + 1 &]