Search: id:A078435
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%I A078435
%S A078435 1,2,5,10,16,25,34,46,59,75,91,110,130,152,177,202,228,258,289,322,356,
%T A078435 392,430,471,511,554,600,647,695,746,799,852,908,965,1025,1086,1150,
%U A078435 1216,1281,1349,1418,1490,1566,1641,1719,1797,1880,1962,2044,2133,2223
%N A078435 Number of composites <= n^2.
%F A078435 a(n)=n^2-A038107(n). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Jun 22 2009]
%e A078435 a(3)=5 because the only composites <= 9 are 1, 4, 6, 8 and 9.
%p A078435 NumComposites := proc(N::posint) local count, i:count := 0:for i from 
               1 to N do if not isprime(i) then count := count + 1 fi:od: count;
               end:seq(NumComposites(k^2), k=1..51); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               May 26 2008
%p A078435 A038107 := proc(n) numtheory[pi]( n^2) ; end: A078435 := proc(n) n^2-A038107(n) 
               ; end: seq(A078435(n),n=1..100) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Jun 22 2009]
%Y A078435 Sequence in context: A084587 A001859 A011903 this_sequence A049815 A047992 
               A079984
%Y A078435 Adjacent sequences: A078432 A078433 A078434 this_sequence A078436 A078437 
               A078438
%K A078435 nonn
%O A078435 1,2
%A A078435 John E. Lenz (jel5010(AT)yahoo.com), Dec 30 2002

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