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 A254010 #25 Jul 18 2023 02:07:53 %S A254010 3,9,24,27,48,57,69,78,87,99,114,153,168,189,192,213,219,234,252,273, %T A254010 303,324,357,372,387,399,402,423,468,498,534,567,573,594,597,609,618, %U A254010 654,672,687,699,708,714,738,759,804,813,864,882,903,918,924,948,969,1032,1038,1128,1182,1197,1203,1233,1242,1269,1308,1353 %N A254010 Numbers k such that 4k+1 and 4(k+1)+1 are primes. %C A254010 Both k and k+1 are terms in A005098. All terms are multiples of 3. %C A254010 4k+1 and 4(k+1)+1 are pairs of consecutive primes. Notice that in all cases, the numbers 4(k-1)+1 and 4(k+2)+1 are not prime as they are multiples of 3. %H A254010 Seiichi Manyama, <a href="/A254010/b254010.txt">Table of n, a(n) for n = 1..10000</a> %p A254010 A254010:=n->`if`(isprime(4*n+1) and isprime(4*(n+1)+1), n, NULL): seq(A254010(n), n=1..2000); # _Wesley Ivan Hurt_, Apr 23 2015 %t A254010 Select[Range[1000], PrimeQ[4 # + 1] && PrimeQ[4 (# + 1) + 1] &] (* _Vincenzo Librandi_, Apr 24 2015 *) %o A254010 (Magma) [n: n in [0..1000] | IsPrime(4*n+1) and IsPrime(4*(n+1)+1)]; // _Vincenzo Librandi_, Apr 24 2015 %Y A254010 Cf. A005098. %K A254010 nonn %O A254010 1,1 %A A254010 _Zak Seidov_, Jan 22 2015