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 A273355 #13 May 22 2025 10:21:44 %S A273355 15370470,15462870,18216510,23726160,30637050,31054740,38907060, %T A273355 39220080,44499900,44678190,60563100,66248550,86219910,87095190, %U A273355 87948780,93773970,96802860,103011990,105953760,105978330,106960410,111219990,116281770 %N A273355 Numbers n such that n - 47, n - 1, n + 1, n + 47 are consecutive primes. %C A273355 This sequence is a subsequence of A014574 (average of twin prime pairs), A249674 (divisible by 30) and A256753. %C A273355 The numbers n - 47 and n + 1 belong to A134122 (p such that p + 46 is the next prime). %C A273355 The numbers n - 47 and n - 1 belong to primes p such that p and p + 48 are primes. %H A273355 Karl V. Keller, Jr., <a href="/A273355/b273355.txt">Table of n, a(n) for n = 1..10000</a> %H A273355 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TwinPrimes.html">Twin Primes</a> %e A273355 15370470 is the average of the four consecutive primes 15370423, 15370469, 15370471, 15370517. %e A273355 15462870 is the average of the four consecutive primes 15462823, 15462869, 15462871, 15462917. %o A273355 (Python) %o A273355 from sympy import isprime,prevprime,nextprime %o A273355 for i in range(0,160000001,6): %o A273355 if isprime(i-1) and isprime(i+1) and prevprime(i-1) == i-47 and nextprime(i+1) == i+47: print (i,end=', ') %o A273355 (PARI) is(n)=isprime(n-1) && isprime(n+1) && precprime(n-2)==n-47 && nextprime(n+2)==n+47 \\ _Charles R Greathouse IV_, Jun 08 2016 %Y A273355 Cf. A014574, A077800 (twin primes), A249674, A256753. %K A273355 nonn %O A273355 1,1 %A A273355 _Karl V. Keller, Jr._, May 20 2016