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%I #12 May 14 2018 03:10:29
%S 17,18,19,23,24,223,224,261,263,264,385,415,417,418,442,812,815,822,
%T 823,824,826,843,846,849,850,851,875,3877,3879,3887,3907,3968,3971,
%U 3973,3975,4247,4249,4269,4270,4327,4394,4399,4802,4804,4806,4809,4810,4812,5072,5078,5087,5088,5095,5426,5427,5483
%N Numbers k where A304356(k)-A304358(k) changes sign.
%H Robert Israel, <a href="/A304488/b304488.txt">Table of n, a(n) for n = 1..565</a>
%e A304356(n)>A304358(n) for n=1..16, but A304356(17)=1039<A304358(17)=1129, so a(1)=17.
%p N:= 10^5:
%p P1:= select(isprime, [seq(i,i=1..N,4)]):
%p P3:= select(isprime, [seq(i,i=3..N,4)]):
%p A1:= select(isprime, P1[1..-3]+P1[2..-2]+P1[3..-1]):
%p A3:= select(isprime, P3[1..-3]+P3[2..-2]+P3[3..-1]):
%p M:= min(nops(A1),nops(A3)):
%p sg:= [seq(signum(A1[i]-A3[i]),i=1..M)]:
%p select(t -> sg[t]<>sg[t-1], [$2..M]);
%Y Cf. A304356, A304358
%K nonn,look
%O 1,1
%A _J. M. Bergot_ and _Robert Israel_, May 13 2018
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