This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A143322 #16 Dec 04 2020 09:24:33 %S A143322 6,21,28,36,50,96,99,216,225,301,325,352,400,441,486,495,496,576,630, %T A143322 676,697,784,847,925,1225,1296,1333,1521,1536,1587,1695,1701,1792, %U A143322 1909,2025,2041,2133,2145,2500,2601,2624,2916,2926,3025,3200,3220,3276,3456 %N A143322 Positive integers k whose sum of distinct prime divisors divides k-1. %H A143322 Amiram Eldar, <a href="/A143322/b143322.txt">Table of n, a(n) for n = 1..10000</a> %e A143322 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. %p A143322 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 %t A143322 Select[Range[2,5000],Divisible[#-1,Total[Transpose[FactorInteger[#]][[1]]]]&] (* _Harvey P. Dale_, Aug 03 2014 *) %o A143322 (PARI) isok(k) = (k!=1) && (((k-1) % vecsum(factor(k)[,1])) == 0); \\ _Michel Marcus_, Dec 04 2020 %Y A143322 Cf. A008472, A089352, A143321. %K A143322 nonn %O A143322 1,1 %A A143322 _Leroy Quet_, Aug 07 2008 %E A143322 Extended by _Emeric Deutsch_, Aug 16 2008