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 A196303 #35 May 16 2025 09:58:05 %S A196303 2,3,7,1471,1483,61627,88651 %N A196303 Primes p such that (p-1)*2^p+1 is also prime. %e A196303 a(1) = 2 because 2 and (2-1)*2^2 + 1 = 5 are both prime. %e A196303 a(2) = 3 because 3 and (3-1)*2^3 + 1 = 17 are both prime. %e A196303 a(3) = 7 because 7 and (7-1)*2^7 + 1 = 769 are both prime. %t A196303 Select[Prime[Range[9000]],PrimeQ[(#-1)2^#+1]&] (* _Harvey P. Dale_, Jan 19 2012 *) %o A196303 (PARI) forprime(n=1,1e4,if(ispseudoprime((n-1)<<n+1),print1(n", "))) \\ _Charles R Greathouse IV_, Oct 09 2011 %Y A196303 Prime terms of A128001. %Y A196303 Cf. A029544, A196421, A196446. %K A196303 nonn %O A196303 1,1 %A A196303 _Juri-Stepan Gerasimov_, Oct 02 2011 %E A196303 a(7) corrected by _Michael S. Branicky_, May 14 2025