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 A216498 #7 Sep 10 2014 12:24:07 %S A216498 157,257,311,353,463,509,691,757,823,839,881,907,941,953,1063,1097, %T A216498 1223,1229,1249,1297,1301,1307,1439,1459,1531,1583,1669,1723,1777, %U A216498 1879,1907,1913,1931,2027,2087,2089,2141,2143,2179,2207,2293,2351,2371,2377,2399,2411 %N A216498 Primes p with property that there exists a number d>0 such that numbers p-k*d, k=1...5, are five primes. %C A216498 Conjecture: only 9198 primes are not in the sequence: 2, 3, ..., 2521081. %e A216498 157 is in the sequence because with d=30: 127, 97, 67, 37, 7 are all primes. %t A216498 prms = 5; fQ[p_] := Module[{d = 1}, While[prms*d < p && Union[PrimeQ[p - Range[prms]*d]] != {True}, d++]; prms*d < p]; Select[Prime[Range[2, PrimePi[2411]]], fQ] (* _T. D. Noe_, Sep 08 2012 *) %o A216498 (PARI) is(n)=my(t); forprime(p=2,n-16,if((n-p)%5==0 && isprime((t=(n-p)/5)+p) && isprime(2*t+p) && isprime(3*t+p) && isprime(4*t+p) && isprime(n), return(1))); 0 \\ _Charles R Greathouse IV_, Sep 10 2014 %Y A216498 Cf. A216495, A094383, A216497, A216468. %K A216498 nonn %O A216498 1,1 %A A216498 _Alex Ratushnyak_, Sep 08 2012