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 A258613 #18 Nov 20 2024 07:42:23 %S A258613 1,2,3,5,7,10,11,13,14,17,19,21,23,26,27,28,29,31,32,33,34,37,41,43, %T A258613 47,50,51,52,53,54,55,57,58,59,60,61,62,65,67,69,71,73,75,77,79,82,83, %U A258613 85,86,88,89,91,92,94,95,97,98,101,103,107,109,111,113,117 %N A258613 Numbers m that are coprime to the largest square <= m, cf. A048760. %H A258613 Reinhard Zumkeller, <a href="/A258613/b258613.txt">Table of n, a(n) for n = 1..10000</a> %H A258613 Joachim Lambek and Leo Moser, <a href="https://doi.org/10.4153/CJM-1955-020-0">On integers n relatively prime to f(n)</a>, Canadian Journal of Mathematics, Vol. 7 (1955), pp. 155-158. %F A258613 A074695(a(n)) = 1. %F A258613 The number of terms that do not exceed x is x/zeta(2) + O(sqrt(x)*log(x)) (Lambek and Moser, 1955). - _Amiram Eldar_, Nov 19 2024 %e A258613 a(8) = 13: GCD(13,A048760(13)) = GCD(13,9) = 1. %e A258613 a(9) = 14: GCD(14,A048760(14)) = GCD(14,9) = 1. %e A258613 GCD(15,A048760(15)) = GCD(15,9) = 3 > 1, therefore 15 is not a term. %t A258613 Select[Range[200],CoprimeQ[#,Floor[Sqrt[#]]^2]&] (* _Harvey P. Dale_, Jun 25 2017 *) %o A258613 (Haskell) %o A258613 a258613 n = a258613_list !! (n-1) %o A258613 a258613_list = filter ((== 1) . a074695) [1..] %o A258613 (PARI) isok(n) = gcd(n, sqrtint(n)^2) == 1; \\ _Michel Marcus_, Jun 06 2015 %Y A258613 Cf. A013661, A074695, A048760, A258614 (complement). %K A258613 nonn %O A258613 1,2 %A A258613 _Reinhard Zumkeller_, Jun 05 2015