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 A349231 #8 Nov 12 2021 04:36:22
%S A349231 47,97,123,341,349,422,474,547,602,723,773,1023,1249,1273,1322,1374,
%T A349231 1419,1447,1518,1663,1673,1847,1861,1923,2006,2022,2055,2105,2149,
%U A349231 2222,2274,2347,2365,2522,2526,2573,2643,2823,2870,3049,3122,3183,3210,3247,3282,3427
%N A349231 Numbers k such that k and k+4 are consecutive squarefree numbers.
%C A349231 The asymptotic density of this sequence is 0.0149788175410999... (Mossinghoff et al., 2021).
%H A349231 Amiram Eldar, <a href="/A349231/b349231.txt">Table of n, a(n) for n = 1..10000</a>
%H A349231 Michael J. Mossinghoff, Tomás Oliveira e Silva, and Tim Trudgian, <a href="https://doi.org/10.1090/mcom/3581">The distribution of k-free numbers</a>, Mathematics of Computation, Vol. 90, No. 328 (2021), pp. 907-929; <a href="https://arxiv.org/abs/1912.04972">arXiv preprint</a>, arXiv:1912.04972 [math.NT], 2019-2020.
%e A349231 47 is a term since 47 and 47 + 4 = 51 = 3*17 are squarefree, and 47 + 1 = 48 = 2^4*3, 47 + 2 = 49 = 7^2 and 47 + 3 = 50 = 2*5^2 are not.
%t A349231 Select[Range[3500], Boole[SquareFreeQ /@ (# + Range[0, 4])] == {1, 0, 0, 0, 1} &]
%Y A349231 Cf. A005117, A007674, A020754, A280892, A349230.
%K A349231 nonn
%O A349231 1,1
%A A349231 _Amiram Eldar_, Nov 11 2021