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 A087560 #21 Feb 01 2025 08:44:29
%S A087560 2,6,6,12,10,30,14,24,18,30,22,60,26,42,30,48,34,90,38,60,42,66,46,
%T A087560 120,50,78,54,84,58,210,62,96,66,102,70,180,74,114,78,120,82,210,86,
%U A087560 132,90,138,94,240,98,150,102,156,106,270,110,168,114,174,118,420,122
%N A087560 Smallest m > n such that gcd(m, n^2) = n.
%C A087560 Equals n multiplied by the least nontrivial number coprime to n. - _Amarnath Murthy_, Nov 20 2005
%H A087560 Ivan Neretin, <a href="/A087560/b087560.txt">Table of n, a(n) for n = 1..10000</a>
%F A087560 a(n) = n*A053669(n).
%F A087560 A000005(a(n)) = 2*A000005(n) = A062011(n). - _Reinhard Zumkeller_, May 17 2006
%F A087560 Sum_{k=1..n} ~ c * n^2 / 2, where c = A249270. - _Amiram Eldar_, Feb 01 2025
%t A087560 Table[n*Select[Prime[Range[Log2[n] + 1]], ! Divisible[n, #] &][[1]], {n, 61}] (* _Ivan Neretin_, May 21 2015 *)
%o A087560 (PARI) a(n) = forprime(p = 2, , if(n%p, return(n*p))); \\ _Amiram Eldar_, Feb 01 2025
%Y A087560 Cf. A000005, A053669, A062011, A119416, A249270.
%K A087560 nonn
%O A087560 1,1
%A A087560 _Reinhard Zumkeller_, Oct 24 2003