Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #7 Sep 06 2019 17:16:26
%S 4,11,17,23,30,34,42,50,54,58,67,73,78,85,95,99,103,111,117,124,128,
%T 140,143,151,157,163,174,174,183,187,197,210,207,217,222,229,235,244,
%U 251,256,261,270,276,285,293,298,304,311,318,327,331,334,347,352,362,366
%N Sum of the number of prime divisors including repetitions between n^2 and (n+1)^2.
%H Amiram Eldar, <a href="/A160907/b160907.txt">Table of n, a(n) for n = 1..10000</a>
%e Between 1^2 and 2^2 we have 0,1,1,2 which sum to 4, so a(1)=4.
%e Between 2^2 and 3^2 we have 2,1,2,1,3,2 which sum to 11, so a(2)=11.
%t f[n_]:=If[n==1,0,Plus@@Last/@FactorInteger[n]]; Table[Sum[f[j],{j,i^2,(i+1)^2}],{i,60}] (* _Ray Chandler_, May 06 2010 *)
%Y Cf. A001222.
%K easy,nonn
%O 1,1
%A _Daniel Tisdale_, May 29 2009
%E Edited and extended by _Ray Chandler_, May 06 2010