cp's OEIS Frontend

A376843 Numbers k such that Omega(k + Omega(k)) = Omega(k) + Omega(Omega(k)), where Omega = A001222.

%I A376843 #11 Oct 08 2024 07:19:29
%S A376843 1,2,6,10,25,26,60,74,78,115,122,123,140,145,146,147,153,156,169,186,
%T A376843 195,205,207,220,222,231,245,253,259,273,314,323,325,341,345,348,355,
%U A376843 361,369,386,387,427,438,453,473,481,505,507,529,536,537,553,554,555,559,561,573,582,618,620,626,635
%N A376843 Numbers k such that Omega(k + Omega(k)) = Omega(k) + Omega(Omega(k)), where Omega = A001222.
%C A376843 Includes semiprimes k such that k + 2 is a triprime.
%H A376843 Robert Israel, <a href="/A376843/b376843.txt">Table of n, a(n) for n = 1..10000</a>
%e A376843 a(5) = 25 is a term because Omega(25) = 2, Omega(2) = 1 and Omega(25 + 2) = Omega(27) = 3 = 2 + 1.
%p A376843 filter:= proc(k) uses numtheory; local s;
%p A376843  s:= bigomega(k);
%p A376843    bigomega(k+s) = s + bigomega(s)
%p A376843 end proc:
%p A376843 select(filter, [$1..1000]);
%Y A376843 Cf. A001222, A001358, A014612, A376830, A376831, A376844, A376848, A376849, A376851.
%K A376843 nonn
%O A376843 1,2
%A A376843 _Robert Israel_, Oct 06 2024