cp's OEIS Frontend

A160649 a(1)=2. a(n) = a(n-1) + A001222(a(n-1)); where A001222(m) is the sum of prime-factorization exponents of m (or, A001222(m) is the number of primes dividing m, with multiplicity).

%I A160649 #20 Mar 01 2023 08:11:30
%S A160649 2,3,4,6,8,11,12,15,17,18,21,23,24,28,31,32,37,38,40,44,47,48,53,54,
%T A160649 58,60,64,70,73,74,76,79,80,85,87,89,90,94,96,102,105,108,113,114,117,
%U A160649 120,125,128,135,139,140,144,150,154,157,158,160,166,168,173,174,177,179
%N A160649 a(1)=2. a(n) = a(n-1) + A001222(a(n-1)); where A001222(m) is the sum of prime-factorization exponents of m (or, A001222(m) is the number of primes dividing m, with multiplicity).
%C A160649 A001222(a(n)) = A160650(n) = a(n+1) - a(n).
%H A160649 G. C. Greubel, <a href="/A160649/b160649.txt">Table of n, a(n) for n = 1..10000</a>
%t A160649 NestList[# + PrimeOmega[#] &, 2, 100] (* _Zak Seidov_, Feb 15 2015 *)
%o A160649 (PARI) lista(nn) = {print1(a=2, ", "); for (n=2, nn, a += bigomega(a); print1(a, ", "););} \\ _Michel Marcus_, May 04 2018
%Y A160649 Cf. A001222, A094222, A160650.
%K A160649 nonn
%O A160649 1,1
%A A160649 _Leroy Quet_, May 21 2009
%E A160649 Extended by _Ray Chandler_, Jun 16 2009