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%I #2 Mar 31 2012 12:38:36
%S 0,0,0,0,8,10,12,0,18,18,28,24,18,30,24,30,30,42,30,18,30,48,30,42,54,
%T 30,24,24,42,54,30,42,36,42,42,42,54,60,60,24,48,30,60,36,60,72,18,84,
%U 36,78,36,42,42,18,24,30,42,60,36,30,84,54,30,48,84,66,48,60,54,72,36
%N Radius of the second-shortest interval (of positive length) centered at prime(n) that has prime endpoints, (zero if no solution exists).
%C 7+-10->primes;but 7-10=-3,so,term #4(for number 7) is 0, 11+-8->primes, 13+-10->primes, 17+-12->primes, 19+-22->primes;but 19-22=-3,so,term #8(for number 19)is 0, 23+-18->primes,..
%t f[n_]:=Module[{a=1},While[ !PrimeQ[n-a]||!PrimeQ[n+a],a++ ];r[n,++a]]; r[n_,k_]:=Module[{a=k},While[ !PrimeQ[n-a]||!PrimeQ[n+a],a++ ];If[a>n,0,a]]; Table[f[Prime[n]],{n,1,5!}]
%Y Cf. A078611
%K nonn
%O 1,5
%A _Vladimir Joseph Stephan Orlovsky_, Apr 26 2010
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