OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
The distinct primes dividing 28 are 2 and 7, since 28 is factored as 2^2 * 7^1. 2 + 7 = 9 is a divisor of 28 - 1 = 27. So 28 is included in this sequence.
MAPLE
with(numtheory): a:=proc(n) local f: f:= factorset(n): if `mod`(n-1, add(f[i], i=1..nops(f)))=0 then n else end if end proc: seq(a(n), n=2..4000); # Emeric Deutsch, Aug 16 2008
MATHEMATICA
Select[Range[2, 5000], Divisible[#-1, Total[Transpose[FactorInteger[#]][[1]]]]&] (* Harvey P. Dale, Aug 03 2014 *)
PROG
(PARI) isok(k) = (k!=1) && (((k-1) % vecsum(factor(k)[, 1])) == 0); \\ Michel Marcus, Dec 04 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 07 2008
EXTENSIONS
Extended by Emeric Deutsch, Aug 16 2008
STATUS
approved