|
%I #8 Apr 05 2020 18:51:34
%S 1,8,16,2,64,4,256,1024,32,128,512,2048,8192,4096,16384,32768,131072,
%T 65536,2097152,262144,524288,1048576,4194304,8388608,16777216,
%U 33554432,67108864,134217728,268435456,536870912,2147483648,1073741824
%N Powers of 2 rearranged such that every partial sum (n>1) is composite.
%H Robert Israel, <a href="/A073925/b073925.txt">Table of n, a(n) for n = 1..3319</a>
%e a(2)=8 because 1+2=3, 1+4=5 are primes and 1+8=9 is composite.
%p N:= 100: # for terms before the first > 2^N
%p Cands:= [seq(2^i,i=0..N)]:
%p Res:= NULL: s:= 0: nC:= N+1:
%p found:= true;
%p while found do
%p found:= false;
%p for i from 1 to nC do
%p if not isprime(s+Cands[i]) then
%p Res:= Res, Cands[i];
%p s:= s + Cands[i];
%p Cands:= subsop(i=NULL, Cands);
%p nC:= nC-1;
%p found:= true;
%p break
%p fi
%p od
%p od:
%p Res; # _Robert Israel_, Apr 05 2020
%Y Cf. A073923, A073924.
%K nonn
%O 1,2
%A _Amarnath Murthy_, Aug 19 2002
%E More terms from _Sascha Kurz_, Feb 01 2003
|
