A164280
a(n) is the sum of the first A129749(n) nonprimes.
Original entry on oeis.org
1, 64, 800, 1452, 207143, 14934568, 18656679, 42721785, 889239450, 1991045973, 6684665064, 11847007536, 127880982508860, 262907426075600, 435646635220423, 58536266213035868, 1777764795352216572, 5690843954660983949, 190101452851104748107, 71537286176000166753366
Offset: 1
A129749(4) = 44; sum of first 44 nonprimes is 1452, so a(4) = 1452.
A160758
Integer averages of first n nonprime numbers for some n.
Original entry on oeis.org
1, 8, 25, 33, 359, 2948, 3291, 4959, 22350, 33357, 60907, 80962, 8276347, 11856980, 15254419, 176009996, 967538242, 1729774831, 9977169279, 193005936726
Offset: 1
The sum of the first 44 nonprimes is 1452. 1452 / 44 = 33, hence 33 is in the sequence.
Cf.
A050248, integer averages of n primes for some n.
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S:=[]; a:=0; c:=0; for n in [1..40000000] do if not IsPrime(n) then a+:=n; c+:=1; if a mod c eq 0 then Append(~S, a div c); end if; end if; end for; S; // Klaus Brockhaus, Aug 11 2009
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lst = {}; s = 0; c = 0; k = 1; While[k < 2700000000, If[ !PrimeQ@k, c++; s = s + k; If[Mod[s, c] == 0, AppendTo[lst, s/c]]]; k++ ]; lst (* Robert G. Wilson v, Jun 05 2009 *)
a=0;lst={};Do[If[ !PrimeQ[n],m=n;a+=m;If[a/n==IntegerPart[a/n],AppendTo[lst,a/n]]],{n,9!}];lst
A179859
Numbers k that divide the sum of the first k noncomposites.
Original entry on oeis.org
1, 3, 7, 225, 487, 735, 50047, 142835, 170209, 249655, 316585343, 374788043, 2460457827, 2803329305, 6860334657, 65397031525, 78658228039
Offset: 1
The sum of the first 7 noncomposites is 42 = 6*7, so 7 is in the sequence.
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lista(kmax) = {my(m = 1, s = 1); print1(1, ", "); forprime(k = 1, kmax, m++; s += k; if(!(s % m), print1(m, ", ")));} \\ Amiram Eldar, May 24 2024
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