cp's OEIS Frontend

A257146 Primitive non-solvable numbers: elements of A056866 not divisible by any earlier term.

%I A257146 #13 Sep 12 2016 12:45:26
%S A257146 60,168,1092,2448,5616,6072,25308,29120,32736,39732,51888,74412,
%T A257146 150348,194472,285852,546312,612468,1285608,1934868,2097024,2165292,
%U A257146 2588772,3594432,3822588,5848428,6324552,7174332,8487168,9095592,10626828,11332452,12576732,14467068,15331992,15927348
%N A257146 Primitive non-solvable numbers: elements of A056866 not divisible by any earlier term.
%C A257146 A number is solvable if and only if it is a positive multiple of a member of this sequence.
%C A257146 There is 1 member of this sequence up to 10^2, 2 up to 10^3, 6 up to 10^4, 12 up to 10^5, 17 up to 10^6, 29 up to 10^7, 49 up to 10^8, 89 up to 10^9, 169 up to 10^10, 321 up to 10^11, 616 up to 10^12, 1188 up to 10^13, 2351 up to 10^14, 4679 up to 10^15, 9350 up to 10^16, 18866 up to 10^17, 38157 up to 10^18, 77534 up to 10^19, 158048 up to 10^20, 323358 up to 10^21, 663159 up to 10^22, and 1363304 up to 10^23. - _Charles R Greathouse IV_, Sep 16 2015
%H A257146 Charles R Greathouse IV, <a href="/A257146/b257146.txt">Table of n, a(n) for n = 1..10000</a>
%F A257146 a(n) >> n^3 log^3 n. - _Charles R Greathouse IV_, Apr 20 2015
%o A257146 (PARI) list(lim)={
%o A257146   my(v=List(),t);
%o A257146   forprime(p=2,,
%o A257146     t=(4^p-1)<<p;
%o A257146     if(t>lim,break);
%o A257146     listput(v,t)
%o A257146   );
%o A257146   forprime(p=3,,
%o A257146     t=3^p*(9^p-1)/2;
%o A257146     if(t>lim,break);
%o A257146     listput(v,t)
%o A257146   );
%o A257146   forprime(p=7,,
%o A257146     t=p*(p^2-1)/2;
%o A257146     if(t>lim,break);
%o A257146     listput(v,t)
%o A257146   );
%o A257146   forprime(p=3,,
%o A257146     t=4^p*(4^p+1)*(2^p-1);
%o A257146     if(t>lim,break);
%o A257146     listput(v,t)
%o A257146   );
%o A257146   if(lim>=5616, listput(v, 5616));
%o A257146   v=Set(v);
%o A257146   for(i=1,#v,
%o A257146     if(v[i]==60 && i>1, next); \\ see below
%o A257146     for(j=i+1,#v,
%o A257146       if(v[j]%v[i]==0, v[j]=60) \\ delete values by setting to v[1]
%o A257146     )
%o A257146   );
%o A257146   Set(v); \\ remove duplicates to combine all 60s
%o A257146 }
%Y A257146 Cf. A056866.
%K A257146 nonn
%O A257146 1,1
%A A257146 _Charles R Greathouse IV_, Apr 16 2015