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A069148
Numbers k such that k*k!/A062758(k) is not an integer where A062758(k) is the product of squares of divisors of k.
2
4, 6, 8, 10, 14, 16, 18, 20, 22, 26, 28, 34, 38, 42, 44, 46, 52, 58, 62, 66, 68, 74, 76, 78, 82, 86, 92, 94, 102, 106, 114, 116, 118, 122, 124, 134, 138, 142, 146, 148, 158, 164, 166, 172, 174, 178, 186, 188, 194, 202, 206, 212, 214, 218, 222, 226, 236, 244, 246
OFFSET
1,1
LINKS
MATHEMATICA
Rest[Position[Table[(n*n!)/(Times@@Divisors[n])^2, {n, 250}], _?(!IntegerQ[ #]&)]//Flatten] (* Harvey P. Dale, Apr 24 2019 *)
Select[Range[250], !Divisible[#!, #^(DivisorSigma[0, #] - 1)] &] (* Amiram Eldar, Jul 07 2022 *)
PROG
(PARI) for(n=1, 320, if((n*(n!))%(n^numdiv(n))>0, print1(n, ", ")))
CROSSREFS
Complement of A069149.
Cf. A001563 (n*n!), A062758.
Sequence in context: A316262 A075124 A067315 * A328144 A327888 A103800
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 08 2002
STATUS
approved