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 A206626 #9 Sep 21 2023 18:47:52 %S A206626 3,17,23,41,71,97,107,113,131,167,197,211,223,233,311,383,397,401,457, %T A206626 467,479,487,491,503,521,617,647,673,691,709,727,743,761,773,809,863, %U A206626 881,887,907,919,937,941,971,991,1009,1013,1097,1117,1171,1213,1249,1283 %N A206626 Primes p such that p + previousprime(p) is a squarefree number. %F A206626 a(n) = A206329(n) - A206462 (n). %e A206626 3+2 = 5 = A206462(1), 17+13 = 30 = A206462(2). %t A206626 Select[Prime[Range[250]],SquareFreeQ[#+NextPrime[#,-1]]&] (* _Harvey P. Dale_, Sep 21 2023 *) %Y A206626 Cf. A001043, A001358, A005117, A206329, A206462. %K A206626 nonn %O A206626 1,1 %A A206626 _Zak Seidov_, Feb 10 2012