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.
%I A234852 #5 Jul 14 2024 13:09:56 %S A234852 1,2,3,4,6,7,9,11,13,14,18,20,23,24,27,29,34,36,40,42,46,47,48,53,58, %T A234852 59,60,62,63,64,66,68,70,71,73,90,95,100,103,105,110,121,122,127,128, %U A234852 132,133,134,141,143,144,153,155,156,162 %N A234852 Indices k of primes p=prime(k) such that prime(p)-p+1 is prime. %F A234852 a(n) = PrimePi(A234695(n)), PrimePi = A000720. %t A234852 Select[Range[200],PrimeQ[Prime[Prime[#]]-Prime[#]+1]&] (* _Harvey P. Dale_, Jul 14 2024 *) %o A234852 (PARI) for(k=1,999,isprime(prime(p=prime(k))-p+1)&&print1(k",")) %Y A234852 Cf. A000040, A000720, A014692, A234850, A234851. %K A234852 nonn %O A234852 1,2 %A A234852 _M. F. Hasler_, Dec 31 2013