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 A078325 #14 Jul 31 2022 07:46:05 %S A078325 2,5,10,17,26,33,37,65,73,82,101,109,122,129,145,170,197,201,217,226, %T A078325 257,290,362,393,401,433,442,485,501,530,577,626,649,677,730,785,842, %U A078325 865,901,962,969,973,1001,1090,1126,1153,1157,1226,1297,1353,1370,1373 %N A078325 Squarefree numbers of the form m*rad(m)+1, where rad = A007947 (squarefree kernel). %H A078325 Reinhard Zumkeller, <a href="/A078325/b078325.txt">Table of n, a(n) for n = 1..10000</a> %t A078325 powQ[n_] := n == 1 || AllTrue[FactorInteger[n][[;; , 2]], # > 1 &]; Select[Range[1400], SquareFreeQ[#] && powQ[# - 1] &] (* _Amiram Eldar_, Jul 31 2022 *) %o A078325 (Haskell) %o A078325 a078325 n = a078325_list !! (n-1) %o A078325 a078325_list = filter ((== 1) . a008966) a224866_list %o A078325 -- _Reinhard Zumkeller_, Jul 23 2013 %o A078325 (PARI) is(n) = n>1 && issquarefree(n) && ispowerful(n-1); \\ _Amiram Eldar_, Jul 31 2022 %Y A078325 Intersection of A005117 and A224866. %Y A078325 Cf. A008966, A078310, A078324. %K A078325 nonn %O A078325 1,1 %A A078325 _Reinhard Zumkeller_, Nov 23 2002