A096480 a(n) = Min{x : A073124(x) = 2n}.
1, 8, 5, 22, 16, 15, 33, 67, 62, 164, 88, 56, 73, 202, 134, 504, 201, 261, 799, 1461, 289, 282, 1309, 1053, 1143, 939, 527, 3531, 2179, 4751, 2461, 5308, 2837, 3983, 1946, 8622, 9488, 12862, 6377, 4653, 7594, 7646, 19251, 22538, 9561, 32509, 26146, 17568
Offset: 1
Keywords
Examples
For n = 4: a(4) = 22 since A073124(22) = prime(1+prime(22)) - prime(prime(22)) = prime(1+79) - prime(79) = 409 - 401 = 8. For n = 5: a(5) = 16 since A073124(16) = prime(1+prime(16)) - prime(prime(16)) = prime(54) - prime(53) = 251 - 241 = 10.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..214
Programs
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Mathematica
Table[Min[Flatten[Position[Table[Prime[Prime[n]+1]- Prime[Prime[n]], {n, 1, 5000}], 2*j]]], {j, 1, 20}] seq[max_] := Module[{p = Prime[Range[max + 1]], m = PrimePi[max], ind, t}, ind = Prime[Range[m]]; t = p[[ind + 1]] - p[[ind]]; TakeWhile[FirstPosition[t, 2*#] & /@ Range[Max[t]] // Flatten, ! MissingQ[#] &]]; seq[10^6] (* Amiram Eldar, Feb 15 2025 *) -
PARI
{m=48;for(n=1,m,k=1;while((prime(prime(k)+1)-prime(prime(k)))!=2*n,k++);print1(k,","))} \\ Klaus Brockhaus, Jun 27 2004
Extensions
a(31)-a(48) from Klaus Brockhaus, Jun 27 2004