A146317 - OEIS

%I #6 Aug 06 2019 08:24:55

%S 5,3,23,17,11,5,3,89,79,67,59,53,43,37,23,19,17,5,163,139,103,79,73,

%T 13,3,2,257,239,227,191,179,173,137,113,89,71,59,53,47,29,23,17,3,367,

%U 347,281,277,269,257,241,239,229,197,179,157,149,131,127,109,107,101,71,61

%N Prime differences of primes subtracted from nearest cube

%C Terms in A146317 + A146318 produce a cube

%H Robert Israel, <a href="/A146317/b146317.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3)=23 because when the prime 23 is subtracted from the cube 64, the result is another prime, 41

%p R:= NULL: count:= 0: p:= 1:

%p while count < 100 do

%p   p:= nextprime(p);

%p   d:= ceil(p^(1/3))^3-p;

%p   if isprime(d) then count:= count+1; R:= R, d fi;

%p od:

%p R; # _Robert Israel_, Aug 06 2019

%o (UBASIC) 10 'cu less pr are prime 20 N=1:O=1 30 A=3:S=sqrt(N) 40 B=N\A 50 if B*A=N then 120 60 A=A+2 70 if A<=S then 40 80 R=O^3:Q=R-N 90 if N<R and N=prmdiv(N) and Q=prmdiv(Q) then print R;N;Q:C=C+1:N=N+2:goto 30 100 if C=30 then stop 120 N=N+2:if N<R then 30:else O=O+1:goto 80

%Y A146315 A146316 A146318

%K easy,nonn,look

%O 1,1

%A _Enoch Haga_, Oct 30 2008