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 A072325 Number of even numbers that cannot be expressed as the difference p-q of two odd primes q < p <= prime(n). 2
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 OFFSET 2,30 COMMENTS If a(n)=0, then Prime[n], called a cluster prime, is in A038134. If a(n)>0 then Prime[n] is in A038133. LINKS Eric Weisstein's World of Mathematics, Cluster Primes EXAMPLE a(25)=1 because Prime[25]=97 and there is 1 even number, 88, that cannot be written as the difference of two odd primes less than or equal to 97. MATHEMATICA m=10000; n=PrimePi[m]-1; p=Table[Prime[i+1], {i, n}]; d=Table[0, {m/2}]; c=Table[0, {n}]; For[i=2, i<=n, i++, For[j=1, j

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Last modified June 5 16:30 EDT 2020. Contains 334852 sequences. (Running on oeis4.)