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 A224980 #6 Apr 22 2013 13:06:09 %S A224980 0,0,1,1,3,2,4,4,5,4,6,8,6,8,7,6,7,12,12,10,12,14,9,8,14,12,16,11,16, %T A224980 14,20,14,10,16,10,24,22,20,11,12,13,28,16,22,18,26,38,22,13,24,14,18, %U A224980 36,18,16,17,18,38,32,28,32,16,30,24,34,20,48,38,17 %N A224980 Number of primes of the form p-q-1 where q is any prime < p = prime(n). %e A224980 For n=5, p=11, there are a(5)=3 solutions: 11-3-1=7, 11-5-1=5, and 11-7-1=3. %t A224980 Table[p = Prime[n]; c = 0; i = 1; While[i < n, If[PrimeQ[p - Prime[i] - 1], c = c + 1]; i++]; c, {n, 69}] %o A224980 (PARI) a(n)=my(p=prime(n),s);forprime(q=2,p-1,s+=isprime(p-q-1));s \\ _Charles R Greathouse IV_, Apr 22 2013 %Y A224980 Cf. A224748, A224908. %K A224980 nonn %O A224980 1,5 %A A224980 _Jayanta Basu_, Apr 22 2013