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 A271349 #15 Feb 16 2025 08:33:33 %S A271349 276672,558828,1050852,1278288,1486908,1625418,2536308,2538918, %T A271349 2690958,2731242,3015162,3252678,3268338,3508278,3711612,4233708, %U A271349 4575912,4717962,5004402,5108352,5404032,5482782,5519082,5525328,5640918,5654358,5995818 %N A271349 Numbers n such that n - 35, n - 1, n + 1 and n + 35 are consecutive primes. %C A271349 This sequence is a subsequence of A014574 (average of twin prime pairs) and A256753. %C A271349 The terms ending in 2 (resp. 8) are congruent to 12 (resp. 18) mod 30. %C A271349 The numbers n - 35 and n + 1 belong to A252091 (p and p + 34 are primes) and A134116 (p such that p + 34 is the next prime). %C A271349 The numbers n - 35 and n - 1 belong to A156104 (p and p + 36 are primes). %H A271349 Karl V. Keller, Jr., <a href="/A271349/b271349.txt">Table of n, a(n) for n = 1..10000</a> %H A271349 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TwinPrimes.html">Twin Primes</a> %e A271349 276672 is the average of the four consecutive primes 276637, 276671, 276673, 276707. %e A271349 558828 is the average of the four consecutive primes 558793, 558827, 558829, 558863. %t A271349 Select[Partition[Prime[Range[500000]],4,1],Differences[#]=={34,2,34}&] [[All, 2]]+1 (* _Harvey P. Dale_, Oct 11 2017 *) %o A271349 (Python) %o A271349 from sympy import isprime,prevprime,nextprime %o A271349 for i in range(0,1000001,6): %o A271349 if isprime(i-1) and isprime(i+1) and prevprime(i-1) == i-35 and nextprime(i+1) == i+35 : print (i,end=', ') %Y A271349 Cf. A014574, A077800 (twin primes), A256753. %K A271349 nonn %O A271349 1,1 %A A271349 _Karl V. Keller, Jr._, Apr 04 2016