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 A261033 #33 Nov 25 2015 02:23:39 %S A261033 3,5,7,9,13 %N A261033 Values of n such that A002110(n) - A007504(n) - 1 is a prime number. %C A261033 Values of n such that difference between product of first n+1 terms of A008578 and sum of first n+1 terms of A008578 is a prime number. %C A261033 Initial primes of the form A002110(n) - A007504(n) - 1 are 19, 2281, 510451. %e A261033 a(1) = 3 because (2*3*5) - (2+3+5) - 1 = 19 is prime. %e A261033 a(2) = 5 because (2*3*5*7*11) - (2+3+5+7+11) - 1 = 2281 is prime. %e A261033 a(3) = 7 because (2*3*5*7*11*13*17) - (2+3+5+7+11+13+17) - 1 = 510451 is prime. %o A261033 (PARI) for(n=1, 1e5, if(ispseudoprime(prod(k=1, n, prime(k)) - sum(k=1, n, prime(k)) - 1), print1(n, ", "))); %Y A261033 Cf. A002110, A007504, A008578, A014284. %K A261033 nonn,more %O A261033 1,1 %A A261033 _Altug Alkan_, Nov 18 2015