cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A096480 a(n) = Min{x : A073124(x) = 2n}.

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%I A096480 #20 Feb 15 2025 09:22:40
%S A096480 1,8,5,22,16,15,33,67,62,164,88,56,73,202,134,504,201,261,799,1461,
%T A096480 289,282,1309,1053,1143,939,527,3531,2179,4751,2461,5308,2837,3983,
%U A096480 1946,8622,9488,12862,6377,4653,7594,7646,19251,22538,9561,32509,26146,17568
%N A096480 a(n) = Min{x : A073124(x) = 2n}.
%H A096480 Amiram Eldar, <a href="/A096480/b096480.txt">Table of n, a(n) for n = 1..214</a>
%e A096480 For n = 4: a(4) = 22 since A073124(22) = prime(1+prime(22)) - prime(prime(22)) = prime(1+79) - prime(79) = 409 - 401 = 8.
%e A096480 For n = 5: a(5) = 16 since A073124(16) = prime(1+prime(16)) - prime(prime(16)) = prime(54) - prime(53) = 251 - 241 = 10.
%t A096480 Table[Min[Flatten[Position[Table[Prime[Prime[n]+1]- Prime[Prime[n]], {n, 1, 5000}], 2*j]]], {j, 1, 20}]
%t A096480 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 *)
%o A096480 (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
%Y A096480 Cf. A000040, A006450, A073124, A072677, A096477, A096478, A096479, A096481, A096482.
%K A096480 nonn
%O A096480 1,2
%A A096480 _Labos Elemer_, Jun 23 2004
%E A096480 a(31)-a(48) from _Klaus Brockhaus_, Jun 27 2004