A143321 Positive integers k whose sum of distinct prime divisors divides k+1.
15, 20, 24, 35, 54, 95, 98, 104, 119, 135, 143, 144, 160, 189, 207, 209, 224, 287, 319, 323, 324, 351, 363, 375, 377, 384, 390, 459, 464, 527, 539, 559, 608, 779, 845, 864, 875, 899, 923, 989, 999, 1000, 1007, 1029, 1189, 1199, 1215, 1280, 1343, 1349, 1375
Offset: 1
Keywords
Examples
The distinct primes dividing 24 are 2 and 3, since 24 is factored as 2^3 *3^1. 2 + 3 = 5 is a divisor of 24 + 1 = 25. So 24 is a term of this sequence.
Links
- David A. Corneth, Table of n, a(n) for n = 1..10000
Programs
-
Maple
with(numtheory): a:= proc(n) local f: f:=factorset(n); if `mod`(n+1, add(i, i=f))=0 then n end if end proc: seq(a(n), n=2..1200); # Emeric Deutsch, Aug 14 2008
-
Mathematica
Select[Range[2,1500],Divisible[#+1,Total[FactorInteger[#][[All,1]]]]&] (* Harvey P. Dale, Aug 27 2022 *)
-
PARI
is(n) = n > 1 && (n + 1) % vecsum(factor(n)[, 1]) == 0 \\ David A. Corneth, Mar 10 2019
Extensions
More terms from Emeric Deutsch, Aug 14 2008
More terms from Max Alekseyev, Mar 10 2009