A078325 Squarefree numbers of the form m*rad(m)+1, where rad = A007947 (squarefree kernel).

2, 5, 10, 17, 26, 33, 37, 65, 73, 82, 101, 109, 122, 129, 145, 170, 197, 201, 217, 226, 257, 290, 362, 393, 401, 433, 442, 485, 501, 530, 577, 626, 649, 677, 730, 785, 842, 865, 901, 962, 969, 973, 1001, 1090, 1126, 1153, 1157, 1226, 1297, 1353, 1370, 1373

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

powQ[n_] := n == 1 || AllTrue[FactorInteger[n][[;; , 2]], # > 1 &]; Select[Range[1400], SquareFreeQ[#] && powQ[# - 1] &] (* Amiram Eldar, Jul 31 2022 *)

Prog

(Haskell)
a078325 n = a078325_list !! (n-1)
a078325_list = filter ((== 1) . a008966) a224866_list
-- Reinhard Zumkeller, Jul 23 2013
(PARI) is(n) = n>1 && issquarefree(n) && ispowerful(n-1); \\ Amiram Eldar, Jul 31 2022

Crossrefs

Intersection of A005117 and A224866.

Cf. A008966, A078310, A078324.

Sequence in context: A078393 A340045 A100292 * A059591 A082607 A303372

Adjacent sequences: A078322 A078323 A078324 * A078326 A078327 A078328

Keyword

nonn

Author

Reinhard Zumkeller, Nov 23 2002

Status

approved