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.

A335271 Full autoinsertable primes are such primes that remain prime after all the possible internal autoinsertions, one at a time.

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%I A335271 #15 Mar 27 2023 09:48:56
%S A335271 131,173,179,191,197,283,293,367,383,401,547,587,641,701,709,757,797,
%T A335271 827,12197,12289,53881,54779,68927,37898818253
%N A335271 Full autoinsertable primes are such primes that remain prime after all the possible internal autoinsertions, one at a time.
%C A335271 Supposed to have only a finite quantity of terms. If the prime has K digits all the possible internal autoinsertions are K-1.
%C A335271 If it exists, the next term is > 2^32.
%e A335271 The prime 131 can be inserted into itself in two positions: 1'131'31, 13'131'1. Both are primes.
%e A335271 The prime 68927 can be inserted into itself in four positions: 6'68927'8927, 68'68927'927, 689'68927'27, 6892'68927'7. All the four are primes.
%o A335271 (PARI) forprime(p=11,10^8,my(v=digits(p),d=#v,f=1);for(i=1,d-1,my(t=concat(concat(v[1..i],v),v[i+1..d]),q=fromdigits(t));if(!isprime(q),f=0;break));if(f,print1(p,", "))) \\ _Hugo Pfoertner_, May 30 2020
%Y A335271 Cf. A247098.
%K A335271 nonn,base,more
%O A335271 1,1
%A A335271 _Carlos Rivera_, May 29 2020
%E A335271 a(24) from _Michael S. Branicky_, Mar 27 2023