A351087 After initial 0, numbers k such that A327860(k) is a multiple of k.

0, 1, 7, 8, 16, 25, 80, 91, 161, 175, 203, 343, 392, 440, 539, 588, 616, 968, 1100, 1225, 1331, 1333, 1337, 1375, 1400, 2556, 3025, 3773, 5112, 5875, 6655, 7280, 7668, 8281, 8575, 8600, 9604, 9800, 10224, 10820, 10868, 11011, 11492, 12595, 12980, 13013, 15925, 17303, 17576, 17875, 20449, 22308, 23677, 24067, 24167

Offset: 1

Author

Antti Karttunen, Feb 03 2022

Keywords

• nonn

Crossrefs

Fixed points of A351083.

Cf. A003415, A276086, A327860.

Cf. A328110 (a subsequence).

Programs

Mathematica

Select[Range[25000], Block[{i, m, n = #, p}, m = i = 1; While[n > 0, p = Prime[i]; m *= p^Mod[n, p]; n = Quotient[n, p]; i++]; # == GCD[#, If[m < 2, 0, m Total[#2/#1 & @@@ FactorInteger[m]]]]] &] (* Michael De Vlieger, Feb 04 2022 *)

PARI

A327860(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= (p^e); s += (e/p); n = n\p; p = nextprime(1+p)); (s*m); };
isA351087(n) = (!n || !(A327860(n)%n));