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

1,3

Links

Table of n, a(n) for n=1..55.

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 *)

Prog

(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));

Crossrefs

Fixed points of A351083.

Cf. A003415, A276086, A327860.

Cf. A328110 (a subsequence).

Sequence in context: A127933 A006878 A022312 * A055661 A287334 A054312

Adjacent sequences: A351084 A351085 A351086 * A351088 A351089 A351090

Keyword

nonn

Author

Antti Karttunen, Feb 03 2022

Status

approved