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Primes for which the weight as defined in A117078 is 7.
1

%I #14 Mar 06 2024 04:48:50

%S 67,83,167,193,251,277,433,487,503,587,601,613,727,823,907,1063,1217,

%T 1231,1553,1663,1777,1861,1873,1973,1987,2083,2281,2293,2351,2377,

%U 2393,2797,2897,3217,3343,3541,3847,4073,4283,4451,4507,4591,4813,4871,5081

%N Primes for which the weight as defined in A117078 is 7.

%C The gap as defined in A001223 of this prime numbers is 4 or 6.

%C The prime numbers in this sequence are of the form (14i-1) (if gap=6) or (14i-3) (if gap=4) with i=(level(n)+1)/2, level(n) defined in A117563.

%H Remi Eismann, <a href="/A118741/b118741.txt">Table of n, a(n) for n=1..10000</a>

%F A117078 : a(n) = smallest k such that prime(n+1) = prime(n) + (prime(n) mod k), or 0 if no such k exists. prime(n) for which k=7.

%t f[n_] := Block[{a, p = Prime[n], np = Prime[n + 1]}, a = Min[Select[Divisors[2*p - np], #1 > np - p & ]]; If[a == Infinity, 0, a]]; Prime@ Select[ Range@695, f@# == 7 &] (* _Robert G. Wilson v_, May 26 2006 *)

%Y Cf. A117078, A117563, A118922, A118924.

%K nonn

%O 1,1

%A _RĂ©mi Eismann_, May 22 2006; May 27 2006; May 04 2007

%E More terms from _Robert G. Wilson v_, May 26 2006